Technical Report Traffic Noise

Document Sample
Technical Report Traffic Noise Powered By Docstoc
					   Traffic Noise
Technical Report
       November 2008
I-70 East Draft Environmental Impact Statement                                                     Traffic Noise Technical Report


                                                       Table of Contents

1.0     INTRODUCTION............................................................................................................... 1
2.0     RESOURCE DEFINITION ................................................................................................ 2
3.0     APPLICABLE LAWS, REGULATIONS, AND GUIDANCE FOR TRAFFIC NOISE
        ANALYSIS ........................................................................................................................ 2
4.0     EXISTING CONDITIONS .................................................................................................. 3
    4.1     METHODOLOGY ........................................................................................................ 3
        4.1.1 Identification of Noise Sensitive Sites.................................................................... 4
        4.1.2 Noise Monitoring ................................................................................................... 4
        4.1.3 STAMINA Model Validation ................................................................................... 4
        4.1.4 Existing Conditions 66 dBA Noise Contours ......................................................... 5
    4.2     FINDINGS ................................................................................................................... 6
        4.2.1 Noise Sensitive Sites............................................................................................. 6
        4.2.2 Noise Monitoring ................................................................................................... 6
        4.2.3 STAMINA Model Validation ................................................................................... 7
        4.2.4 Existing Conditions 66 dBA Noise Contours ......................................................... 7
5.0     DESCRIPTION OF ALTERNATIVES ............................................................................... 8
6.0     EFFECTS ANALYSIS..................................................................................................... 11
    6.1     METHODOLOGY ...................................................................................................... 11
    6.2     ALTERNATIVE EFFECTS ........................................................................................ 14
        6.2.1 Section 1 – I-25 to Brighton Boulevard................................................................ 14
        6.2.2 Section 2 – Brighton Boulevard to Colorado Boulevard ...................................... 16
        6.2.3 Section 3 – Colorado Boulevard to I-270............................................................. 21
        6.2.4 Section 4 – I-270 to I-225 .................................................................................... 23
        6.2.5 Section 5 – I-225 to Tower Road......................................................................... 25
7.0     MITIGATION ................................................................................................................... 27
    7.1     MITIGATION STRATEGIES...................................................................................... 27
    7.2     PROPOSED MITIGATION ........................................................................................ 29
    7.3     CONCLUSIONS AND RECOMMENDATIONS ......................................................... 34
    7.4     CONSTRUCTION NOISE ......................................................................................... 35
    7.5     LOCAL AGENCY COORDINATION ......................................................................... 36
8.0     REFERENCES................................................................................................................ 37

                                                          List of Figures

Figure 1 Project Area ....................................................................................................................1
Figure 2 Noise Sensitive Sites ......................................................................................................7
Figure 3 Alternative 1....................................................................................................................9
Figure 4 Alternative 3....................................................................................................................9
Figure 5 Alternative 4..................................................................................................................10
Figure 6 Alternative 6..................................................................................................................10
Figure 7 Lane Representations in STAMINA..............................................................................12
Figure 8 Section 1 Receiver Locations and Noise Contours ......................................................16
Figure 9 Section 2 Existing Alignment Receiver Locations and Noise Contours ........................20
Figure 10 Section 2 Realignment Receiver Locations and Noise Contours ...............................21
Figure 11 Section 3 Receiver Locations and Noise Contours ....................................................23
Figure 12 Section 4 Receiver Locations and Noise Contours ....................................................25
Figure 13 Section 5 Receiver Locations and Noise Contours ....................................................26
Figure 14 Section 2 Barriers – Realignment Alternatives 4 and 6 West .....................................30
Figure 15 Section 2 Barriers – Existing Alignment Alternatives 4 and 6 East.............................31
Figure 16 Section 2 Barriers – Existing Alignment Alternatives 1 and 3 North ...........................31

November 2008                                                                                                                             i
Traffic Noise Technical Report                                         I-70 East Draft Environmental Impact Statement


Figure 17 Section 2 Barriers – Existing Alignment Alternatives 1 and 3 South...........................32
Figure 18 Section 3 Barriers – Existing Alignment Alternative 4 West and East ........................33
Figure 19 Section 3 Barriers – Existing Alignment Alternative 6 West and East ........................33


                                                       List of Tables

Table 1 CDOT Noise Abatement Criteria......................................................................................4
Table 2 LOS D Traffic Modeling Assumptions ..............................................................................5
Table 3 Section 1 General Contours...........................................................................................14
Table 4 Section 1 Noise Model Results ......................................................................................15
Table 5 Section 2 General Contours...........................................................................................17
Table 6 Section 2 Noise Model Results ......................................................................................17
Table 7 Section 3 General Contours...........................................................................................21
Table 8 Section 3 Model Results ................................................................................................22
Table 9 Section 4 General Contours...........................................................................................23
Table 10 Section 4 Noise Model Results ....................................................................................24
Table 11 Section 5 General Contours.........................................................................................25
Table 12 Section 5 Noise Model Results ....................................................................................26

                                                   List of Appendices

Appendix A          Monitoring Results
Appendix B          Colorado Department of Transportation Noise Abatement Determination Forms




ii                                                                                                            November 2008
I-70 East Draft Environmental Impact Statement                    Traffic Noise Technical Report


                                        List of Acronyms

A                                                  M
                                                   mph     miles per hour
B
                                                   N
C                                                  NAC     Noise Abatement Criteria
CDOT     Colorado Department of                    NEPA    National Environmental Policy Act
         Transportation
                                                   O
D
dB     decibels                                    P
dBA    A-weighted levels
DEIS   Draft Environmental Impact                  Q
       Statement
Denver City and County of Denver                   R
                                                   RTD     Regional Transportation District
E
EIS      Environmental Impact Statement            S

F                                                  T
FEIS     Final Environmental Impact
         Statement                                 U
FHWA     Federal Highway Administration
FTA      Federal Transit Administration
                                                   V
G
                                                   W
H
                                                   X
I
                                                   Y
J
                                                   Z
K

L
Leq      equivalent sound level
LOS      level of service




November 2008                                                                                 iii
Traffic Noise Technical Report                        I-70 East Draft Environmental Impact Statement




                                 This page intentionally left blank.




iv                                                                                  November 2008
I-70 East Draft Environmental Impact Statement                       Traffic Noise Technical Report


1.0    INTRODUCTION
The I-70 East Environmental Impact Statement (EIS) is a joint effort between the Federal
Highway Administration (FHWA) and the Colorado Department of Transportation (CDOT). The
intent of the EIS is to identify potential highway improvements along I-70 in the Denver
metropolitan area between I-25 and Tower Road and to assess their potential effects on the
human and natural environment.

Analysis of I-70 through this area began in June 2003 as part of the I-70 East Corridor EIS, a
joint effort conducted by CDOT, FHWA, the Regional Transportation District (RTD), the
Federal Transit Administration (FTA), and the City and County of Denver (Denver). In June
2006, the highway and transit elements of the I-70 East Corridor EIS were divided into two
separate projects because they serve different travel markets, are located in different corridors,
and have different funding sources. The I-70 East EIS focuses on potential I-70 improvements
and the transit improvements are now being evaluated under the East Corridor EIS, conducted by
RTD and FTA.

                                             Figure 1
                                           Project Area




The project area, shown in Figure 1, includes portions of Denver, Commerce City, Aurora, and
Adams County. The area covers established neighborhoods on the west end of the corridor
including Globeville, Elyria, Swansea, Cole, Clayton, and Northeast Park Hill. The emerging
residential and commercial areas on the east include Stapleton (former Stapleton Airport),
Montbello, Green Valley Ranch, and Gateway. These communities are diverse in their character

November 2008                                                                                    1
Traffic Noise Technical Report                         I-70 East Draft Environmental Impact Statement


and history, providing a wide variety of residential, commercial, public facility, and institutional
land uses. Adding to the complexity of the project area is the presence of the National Western
Complex as a major travel destination and redevelopment.

This report discusses traffic noise as it relates to the I-70 East EIS, including existing conditions
in the corridor, resource effect analysis, and mitigation measures.

2.0     RESOURCE DEFINITION
Noise is generally defined as unwanted or undesirable sound. Noise typically affects humans in
three different ways, noise intensity or level, noise frequency, and noise variation with time

Noise intensity is determined by how sound pressure fluctuates and is expressed in decibels (dB).
The range of noise normally encountered can be expressed by values between 0 and 120 dB on
the dB scale. A three-dB change in sound level generally represents a barely-noticeable change
in noise level, whereas a ten-dB change would typically be perceived as a doubling of loudness.
The frequency of noise is related to the tone or pitch of the sound and is expressed in terms of
cycles per second or Hertz. The human ear can detect a wide range of frequencies from about 20
Hertz to 17,000 Hertz. The A-weighting system is commonly used when measuring noise to
provide a value that represents human response because human sensitivity to sound varies from
person to person. Noise levels measured using this system are called “A-weighted” levels, and
are expressed as dBA.

Because noise fluctuates during the course of a day, it is common practice to condense all of this
information into a single number, known as an equivalent sound level (Leq). Leq represents a
steady sound level over a specified time period (typically 15 minutes).

3.0     APPLICABLE LAWS, REGULATIONS, AND GUIDANCE FOR
        TRAFFIC NOISE ANALYSIS
This section discusses applicable laws, regulations, and guidance as they pertain to the analysis
of traffic noise in this EIS.

National Environmental Policy Act
The National Environmental Policy Act (NEPA) of 1969, as amended, (42 United States Code
4321 et seq., Public Law 91-190, 83 Stat. 852), mandates that transportation decisions involving
federal funds and approvals consider social, economic, and environmental factors in the
decision-making process. NEPA also requires that agencies making such decisions consult with
other agencies, involve the public, disclose information, investigate the environmental effects of
a reasonable range of alternatives, and prepare a detailed statement of the environmental effects
of the alternatives.

Council on Environmental Quality Regulations
Council on Environmental Quality Regulations Part 1502, “Environmental Impact Statement,”
(40 Code of Federal Regulations 1502.14), requires that an EIS be prepared when a proposed
action is projected to have a significant impact on the quality of the human environment. Under
the Council on Environmental Quality regulations EIS documents must provide full and fair
discussion of significant environmental impacts and inform decision makers and the public about
project alternatives.

2                                                                                     November 2008
I-70 East Draft Environmental Impact Statement                        Traffic Noise Technical Report


Procedures for Abatement of Highway Traffic Noise and Construction Noise
Title 23 Code of Federal Regulations Part 772 codifies procedures for considering noise studies
in NEPA federal-aid processes and establishes requirements for transferring traffic noise
information to local planning agencies to assist in their land use planning activities.

FHWA Highway Traffic Noise Analysis and Abatement: Policy and Guidance
FHWA’s Highway Traffic Noise Analysis and Abatement Policy and Guidance defines FHWA
procedures for abatement of highway traffic noise and construction noise and establishes
standards for mitigating highway traffic noise. The document provides FHWA policies and
guidance for the analysis and abatement of highway traffic noise based on 23 Code of Federal
Regulations 772.

FHWA Measurement of Highway-Related Noise
FHWA’s Measurement of Highway-Related Noise Policy is intended to provide a uniform
guidance reference for highway noise practitioners and researchers, addressing measurement and
analysis instrumentation, site selection, measurement procedures, data reduction, and analysis
techniques.

CDOT Noise Analysis and Abatement Guidelines
The CDOT Noise Analysis and Abatement Guidelines (2002a) implements the FHWA noise
regulation for CDOT projects. It provides guidance on conducting traffic noise studies, analyzing
abatement options, investigating construction noise levels, and coordinating noise levels with
local land use planning officials.

4.0    EXISTING CONDITIONS
The project area is almost entirely urbanized with varied land uses. At the west end of the project
area, a mix of residential and commercial properties gradually changes to primarily
commercial/industrial uses near Colorado Boulevard. Continuing east, residential and
commercial development begin to appear east of I-225. Major new developments are planned or
on-going within the project area in the Stapleton Redevelopment Area between Quebec Street
and Havana Street and in the Gateway area north of I-70 and east of Peña Boulevard.

4.1    METHODOLOGY
The existing conditions noise analysis was performed in accordance with the requirements of
Title 23 Code of Federal Regulations Part 772, Procedures for Abatement of Highway Traffic
Noise and Construction Noise, using methodology established by CDOT in their Noise Analysis
and Abatement Guidelines. Predicted noise levels were produced using the FHWA traffic noise
model STAMINA 2.0 with Colorado vehicle noise emissions (1994). All measured and predicted
noise levels are expressed in dB using a dBA weighting. The dBA weighting of the dB scale
most closely approximates the response characteristics of the human ear. All noise levels are
reported as hourly equivalent noise levels. The hourly equivalent noise levels are defined as the
equivalent steady-state sound level that, in a given hourly period, contains the same acoustic
energy as the time-varying sound for the same hourly period.

Noise from traffic emanates from four primary sources: tire/road interface, engines,
aerodynamics, and exhaust stacks. The dBA weighted numbers are used to determine the effect
upon potential noise sensitive sites. Each of these is considered in the STAMINA 2.0 model.

November 2008                                                                                     3
Traffic Noise Technical Report                             I-70 East Draft Environmental Impact Statement


4.1.1 Identification of Noise Sensitive Sites
Noise sensitive sites are defined as any property (owner-occupied, rented, or leased) where
frequent exterior human use occurs and where a lowered noise level would be of benefit. CDOT
has established noise levels at which noise abatement must be considered for various types of
noise sensitive sites. These noise levels are referred to as the Noise Abatement Criteria (NAC).
As presented in Table 1, the NAC vary according to the land use activity category. Noise
abatement measures must be considered when either of the following is true:
    • Predicted traffic noise levels meet or exceed the NAC.
    • A substantial noise increase of 10 dBA over existing conditions is predicted.

                                             Table 1
                                   CDOT Noise Abatement Criteria

    Activity
                 Leq(h)                      Description of Land Use Activity Category
    Category
                             Lands on which serenity and quiet are of extraordinary significance and
                  56
       A                     serve an important public need and where the preservation of those qualities
               (Exterior)
                             is essential if the area is to continue to serve its intended purpose.
                  66         Picnic areas, recreation areas, playgrounds, active sports areas, parks,
       B
               (Exterior)    residences, motels, hotels, schools, churches, libraries, and hospitals.
                  71
       C                     Developed lands, properties, or activities not included in Categories A or B.
               (Exterior)
       D            --       Undeveloped lands.
                    51       Residences, motels, hotels, public meeting rooms, schools, churches,
       E
                (Interior)   libraries, hospitals, and auditoriums.
Source: CDOT Noise Analysis and Abatement Guidelines (2002a)



4.1.2 Noise Monitoring
To validate the computer noise model (see Section 4.1.3, STAMINA Model Validation), field
measurements were taken within the project area following procedures documented in FHWA’s
Measurement of Highway-Related Noise Policy. Field measurements were obtained using Larson
Davis 812 and Larson Davis 712 Sound Level Meters. Meters, microphones, and calibrators are
calibrated to factory settings at Larson Davis’s Utah lab annually. Monitoring events generally
lasted 15 minutes, but 1-hour and 24-hour measurements were also taken. Noise monitors were
calibrated using a Larson Davis sound level calibrator before each measurement.

4.1.3 STAMINA Model Validation
Site selections for the field validation measurements were conducted in the vicinity of noise
sensitive sites, where safe access to monitoring sites existed, where a representative sampling of
free-flow traffic could be obtained, and where roadway geometry remained relatively constant.

Measurements may be taken at anytime; however, standard practice states it is best to measure
when traffic is moving at or near the posted speed limit. At least two measurements were taken at
each validation location and averaged to avoid skewed results. Traffic volumes and vehicle
classifications (car, truck, heavy truck) were recorded with hand counters during noise readings.
Volumes and classifications for each validation are included in Appendix A. Traffic speeds were

4                                                                                           November 2008
I-70 East Draft Environmental Impact Statement                             Traffic Noise Technical Report


estimated by driving in mainstream traffic during the measurement. Speeds were typically at
posted speed limits. A STAMINA noise model was built to simulate traffic and roadway
conditions for each validation site. Modeled noise levels were compared to measured noise
levels. Validation of the STAMINA model occurred when measured and modeled values are
within 3 dBA. Validation of the model was necessary before STAMINA can be used to predict
noise levels for existing, no-action, and build project scenarios.

At the start of the validation process, validation sites were selected throughout the corridor by
reviewing project aerials. Multiple sites were chosen to represent the entire project area.
Successful validation of sites in different neighborhoods with different roadway geometry, traffic
conditions, terrain lines, and shielding (buildings and other impediments to the propagation of
noise) provided high confidence in the STAMINA model results and subsequent decisions made
in the remaining portions of the noise study.

4.1.4 Existing Conditions 66 dBA Noise Contours
Based on CDOT’s Noise Analysis and Abatement Guidelines, 66 dBA was used as the approach
noise level in the analysis of the existing conditions in the study area (see Table 1). The distance
from the edge of pavement to the 66 dBA noise contour under existing conditions was estimated
using the STAMINA computer model, traffic volumes from the loudest hour existing conditions
(based upon existing traffic studies and Highway Capacity Manual), and posted speed limits.

Noise studies typically use worst-case noise conditions in determining the dBA. Generally,
worst-case level of service (LOS) C conditions are considered in noise analysis because the
greatest volume is traveling at the highest speeds. Given the operations along I-70 in this area,
the Highway Capacity Manual LOS curves were used to demonstrate that LOS D conditions
result in the worst-case noise conditions in the project area. Data for a typical freeway segment
having characteristics similar to I-70 were used as input to determine the maximum number of
vehicles (per hour) traveling at five miles per hour (mph) above the posted speed limit. These
traffic volumes were used in developing the 66 dBA noise contours.

Traffic volumes on relatively low volume ramps and side streets were not considered in the
model because the ramps’ speeds were below the program threshold of 30 mph or the volumes
were minimal. However, ramps carrying significant volumes of traffic were considered as these
ramps impacted noise levels. These included the I-70 to I-25 ramps near the Globeville area and
the ramps at I-225 and at I-270. Traffic volumes and vehicle mixes that were used in developing
the 66 dBA contours are presented in Table 2. It should be noted that all segments of I-70 within
the project area exceed optimal traffic conditions (LOS A, B, or C) at some time during a 24-
hour period, thus LOS D was used for all segments of I-70 at the loudest hours.
                                              Table 2
                               LOS D Traffic Modeling Assumptions

                                                            Speed    Truck Percentage
                      Roadway Type                Volume*
                                                            (mph) (total - medium/heavy)
                Highway (I-70)                     1,855     55         (10 - 40/60)
                Ramps                              1,000     45         (18 - 50/50)
                Frontage roads                      850      40         (20 - 50/50)
                Cross streets (interchanges)        850      40         (20 - 65/35)
              *Passenger cars per hour per lane

November 2008                                                                                          5
Traffic Noise Technical Report                          I-70 East Draft Environmental Impact Statement


4.2     FINDINGS
The existing conditions analysis identified potential noise sensitive sites in the project area and
described the noise monitoring process, modeling process, and existing conditions results.

4.2.1 Noise Sensitive Sites
The existing land uses adjacent to I-70 consist of residential, commercial, and light industrial
uses. Existing residences, hotels, historic structures, multi-use recreational trails, parks, schools,
and planned Land Use Category B sites in the Stapleton redevelopment and Tower Road areas
were identified as noise sensitive sites within the project area. Category B sites were identified
by reviewing land use maps and project aerials, and verified through field surveys. Noise
sensitive areas and noise monitoring locations are shown in Figure 2.

4.2.2 Noise Monitoring
The 2005 noise monitoring included 15-minute, 1-hour, and 24-hour measurements. Most
measurements were taken in Land Use Category B areas.

Detail regarding each measurement is included in Appendix A (Table A-1) along with field notes
for each measurement. The 15-minute measurements were used to validate the STAMINA
model, develop baseline ambient (surrounding environment) noise levels, and gain a better
understanding of how multiple noise sources may be affecting a noise sensitive site. The 24-hour
noise measurements provided insight on the noise peaks and valleys during a 24-hour period and
helped determine the worst-case traffic conditions for noise. Time history graphs for the 24-hour
noise measurements have been included in Appendix A. Two observations can be made:
    • Existing noise levels at these 24-hour locations exceed 66 dBA for most of the 24-hour
        period
    • Early morning rush hour noise levels are higher, but their duration is shorter than evening
        rush hour




6                                                                                      November 2008
I-70 East Draft Environmental Impact Statement                          Traffic Noise Technical Report


                                            Figure 2
                                      Noise Sensitive Sites




4.2.3 STAMINA Model Validation
Data collected in the field, including noise readings, atmospheric information, noise sources, and
other site specific information were used along with existing roadway configurations, traffic
volumes, speeds, and vehicle mix to calibrate and validate the model at the locations identified as
Land Use Category B areas. For the most part, the averages of the measured and modeled values
were within the acceptable range of plus or minus 3 dBA. There were certain individual
instances where a trial was outside of this range, such as reading 13 at Swansea Elementary. At
this location the modeled Leq value was 4.0 dBA higher than the field measurement during one
reading. This is due in part to the unique noise environment that occurs in close proximity to the
viaduct section. Because the measured and modeled variances over 3 dBA were rare and
occurred in unique noise environments the model was considered acceptable for use.

4.2.4 Existing Conditions 66 dBA Noise Contours
The existing conditions 66 dBA contour is a line, roughly parallel with I-70, where a 66 dBA
noise level is expected. This distance is generally between 300 and 350 feet from the edge of
pavement. Noise levels may be higher for points closer to I-70. The contour considers hard and
soft propagation surfaces, terrain, existing noise barriers, and limited shielding effects from other
buildings. Hard and soft propagation surfaces refer to land cover types such as grass (soft
surface) or pavement (hard surface). Noise waves reflect or bounce easier over hard surfaces
allowing noise waves to travel farther. Soft surfaces diffract or break-up noise waves making the
wave dissipate sooner and not travel as far. These features may cause the contour to deviate.

November 2008                                                                                       7
Traffic Noise Technical Report                       I-70 East Draft Environmental Impact Statement


Examples of this can be seen near existing noise barriers in the Globeville neighborhood (west
end of the project) and existing noise barriers west of Chambers Road (north side of I-70).
Contours at these points rest on top of the noise barriers because the barriers are effective at
reducing noise levels behind the wall to less than 66 dBA. The noise contour does not account
for other noises sources (e.g., Nestlé Purina Petcare Company). Limited intersecting or adjacent
streets were used in the noise model. Figure 8 through Figure 13 in Section 6.0 show maps of
the modeled receiver locations and 66 dBA noise contours for Sections 1 through 5.

5.0     DESCRIPTION OF ALTERNATIVES
The I-70 East EIS is examining potential social, environmental, and economic resources effects
of possible improvements to I-70. Consistent with federal regulation, the EIS evaluates potential
effects that might result from a No-Action Alternative and a set of highway build alternatives.
For this EIS, the No-Action Alternative is defined as replacement of the existing viaduct between
Brighton Boulevard and Colorado Boulevard with no additional lanes or other capacity
improvements. The four build alternatives are evaluated in the Draft EIS (DEIS) are shown in
Figure 3 through Figure 6 and include:
    • Alternative 1. Adding new general purpose lanes on the existing I-70 alignment along
        the length of the corridor with interchange improvements throughout the corridor and
        consideration of a new interchange at Central Park Boulevard.
    • Alternative 3. Adding a combination of general purpose lanes and tolled express lanes
        on the existing I-70 alignment, with tolled express lanes added from Colorado Boulevard
        to Chambers Road, and general purpose lanes added west of Colorado Boulevard and east
        of Chambers Road. Interchange improvements would be made per Alternative 1.
    • Alternative 4. Placing I-70 on new alignment beginning at Brighton Boulevard and
        extending northeast toward a new interchange with I-270 near Colorado Boulevard, then
        following I-270 southeast to its existing interchange with I-70. New general purpose
        lanes would be added to I-70 along its entire length within the study area. New
        interchanges would be provided along the realignment at Brighton Boulevard, Colorado
        Boulevard/Vasquez Boulevard with interchange improvements at the remaining
        interchanges along the corridor and consideration of a new interchange at Central Park
        Boulevard. The existing viaduct east of Brighton Boulevard would be removed and 46th
        Avenue would serve as a four- to six-lane roadway along the existing I-70 alignment
        between Brighton Boulevard and Quebec Street.
    • Alternative 6. As with Alternative 4, placing I-70 on new alignment beginning at
        Brighton Boulevard and along a portion of I-270. General purpose lanes would be added
        from I-25 to west of Brighton Boulevard on the realignment and from Chambers Road to
        Tower Road on the existing alignment. Tolled express lanes would be developed between
        Brighton Boulevard and Chambers Road. Access improvements would be made per
        Alternative 4. The existing viaduct east of Brighton Boulevard would be removed and
        46th Avenue would serve as a four- to six-lane roadway along the existing I-70 alignment
        between Brighton Boulevard and Quebec Street.

Different options are being evaluated within the alternatives. These options include shifting to
the north or south between Brighton Boulevard and Quebec Street on Alternatives 1 and 3, and
two options for connecting the realignment to existing I-70 near Brighton Boulevard. For more
detail on alternatives, see the I-70 East EIS Alternative Analysis and Screening Process Report
(2008).

8                                                                                  November 2008
I-70 East Draft Environmental Impact Statement             Traffic Noise Technical Report


                                             Figure 3
                                           Alternative 1




                                             Figure 4
                                           Alternative 3




November 2008                                                                          9
Traffic Noise Technical Report             I-70 East Draft Environmental Impact Statement


                                   Figure 5
                                 Alternative 4




                                   Figure 6
                                 Alternative 6




10                                                                       November 2008
I-70 East Draft Environmental Impact Statement                          Traffic Noise Technical Report


6.0    EFFECTS ANALYSIS
The effect analysis presents the results of traffic noise effects that would result from
implementation of project alternatives and discusses mitigation measures to minimize adverse
effects. The effect assessment for the I-70 East EIS compares the build alternatives to a No-
Action Alternative.

6.1    METHODOLOGY
The assessment of noise effects from traffic operations is based on a comparison of existing and
projected future noise exposure for noise sensitive land use categories. At the start of the traffic
noise study several methodologies were proposed. The methodologies were approved by the
project management team with an understanding that some flexibility should be built in for
special issues that surfaced. The following describes the methodologies followed for the noise
effects analysis.

Noise Prediction Model
STAMINA 2.0 (Colorado emissions) was used for all traffic noise modeling. Colorado emissions
refer to modifications made to the initial STAMINA model during development, to account for
Colorado’s specific conditions (e.g., thinner air at higher elevations).

Shielding
No shielding was assigned to second and third row receivers. This guidance was provided by
CDOT.

Placement of Receivers
Receiver locations were placed in the middle of the property closest to the noise source, unless
there was another apparent area of frequent outdoor human use.

Traffic and Speed
As discussed previously, monitoring was conducted during time periods having the worst-case
noise conditions. The same is true for modeling. Worst-case conditions on the I-70 mainline
were at volumes determined using the Highway Capacity Manual to be at a free flow speed of 55
mph and LOS D. Table 2 in Section 4.1.4, Existing Conditions 66 dBA Noise Contours provides
the volume, speed, and truck percentage assumptions for the traffic noise modeling.

Input Data
Vertical and horizontal data for roadways, receivers, and walls was gained from project area
mapping and was used for noise modeling. Microstation design files, field reviews, and
Geographic Information System were used to provide accurate vertical/horizontal data.
Representative lane configurations and receiver locations were created in Geographic
Information System prior to STAMINA input.

Number of Lanes in STAMINA Model (Existing and Future Scenarios)
The STAMINA model limits the number of roadways that may be used in a specific model.
Roadways are typically consolidated to facilitate the modeling of complex roadway systems.

Figure 7 shows the configurations that were used for the modeling efforts. A single modeled
travel lane was used to represent two- or three-directional lanes in the STAMINA model runs

November 2008                                                                                      11
Traffic Noise Technical Report                      I-70 East Draft Environmental Impact Statement


and two modeled travel lanes were used to represent four-lane configurations. Two modeled
travel lanes were also used to represent the five-lane and six-lane configurations. Figure 7
highlights the number and placement of representative lanes in the STAMINA noise model. The
red arrow in the figure represents the location of the modeled lane in the STAMINA model.

                                            Figure 7
                                 Lane Representations in STAMINA




               Three Lane                                         Four Lane




                Five Lane                                        Six Lane




12                                                                                November 2008
I-70 East Draft Environmental Impact Statement                         Traffic Noise Technical Report




Two-lane ramps and collector-distributors required one modeled lane in STAMINA. The lane
was modeled down the center of both lanes. Three-lane frontage roads and ramps also required
one modeled lane in STAMINA, but the lane was modeled down the center of the middle lane.

One modeled lane of traffic was used to represent cross streets unless the proposed cross streets
had four or more lanes in each direction.

Interchange Modeling
Because it is difficult to model complex interchanges in STAMINA, only high volume ramps
adjacent to noise sensitive areas were included. Analysis of other ramps demonstrated that they
had little effect on noise sensitive areas.


Apartments/Hotels/Condos
Noise sensitive structures with multiple floors having areas of frequent human outdoor use were
analyzed/modeled. The noise analysis included one floor above existing grade of the adjacent
roadway and all floors below it. For example, if the second floor of an apartment building is at
the same elevation as the adjacent roadway, the first, second, and third floors were included in
the existing conditions noise analysis (this assumes the first, second, and third floors have
different tenants). Pool areas and playgrounds associated with these land uses were also included
in the noise analysis.

Arterial Streets/Alternate Corridors
The traffic noise modeling included noise sensitive areas along major arterial streets within 500
feet of I-70. Additional traffic corridors were added to the existing conditions noise study as they
were identified in the DEIS process.

Viaducts
Since STAMINA does not model viaducts effectively, a noise model was constructed replicating
I-70 traffic variables (speed, volume, and mix) and a separate noise model was constructed to
represent the viaduct noise input variables. The results of these two models were combined
through dB addition to get an overall noise level.

Severe Traffic Noise
Severe traffic noise conditions (75 dBA or greater) are present in the corridor. Additional
monitoring and modeling for severe traffic noise may be required for areas receiving traffic noise
at or above 75 dBA in the Final EIS (FEIS).

Abatement Goals
The project team analyzed barriers to achieve at least 5 dBA of insertion loss, which is the
amount of noise reduction from proposed abatement, with a goal of 10 dBA insertion loss. In
many cases, analyses of barriers that provide a 10 dBA insertion loss goal were considered to be
infeasible due to extraordinarily high wall heights required.

Rounding
Noise values were not rounded or truncated. Values are reported to the tenth of a dBA.


November 2008                                                                                     13
Traffic Noise Technical Report                               I-70 East Draft Environmental Impact Statement


6.2       ALTERNATIVE EFFECTS
The evaluation of alternative effects is organized by project area sections and focuses on specific
locales or communities of sensitive NAC B receivers shown previously in Figure 2. To aid in the
comparison of alternatives for these NAC B sensitive receiver areas or communities, tables were
developed comparing the existing noise levels and predicted 2030 noise levels for the various
alternatives. In addition to these tables, aerial photographs of each area are shown with the
receiver locations and the approximate 66 dBA contour line for each alternative is provided for
general information and is not to determine impacts. The location shown for the 66 dBA contour
line does not assume any potential mitigation strategies. Efforts were made to include all
representative receivers in the analysis of each alternative. However, some receivers evaluated in
one alternative were directly impacted by another alternative. These receivers are still presented
in the tables to allow for comparison of the alternative to which they are valid.

Graphic depictions of contours were not developed for NAC C areas, commercial or industrial
type developed lands. As NAC B areas are more sensitive to noise impacts, the focus of the
analysis was on those areas and a further detailed analysis of commercial areas was not
performed as part of this study.

6.2.1 Section 1 – I-25 to Brighton Boulevard
Section 1 includes the Globeville neighborhood, which has existing noise barriers along I-70. No
construction is proposed in Section 1 for any of the alternatives. The existing pavement is
proposed to be restriped for an additional lane eastbound. Residential properties are the primary
land use from I-25 to Washington Street, with a stretch from Washington Street to Brighton
Boulevard primarily NAC C (e.g., the Denver Coliseum and National Western Complex).

The general NAC B and NAC C contour distances from edge of pavement are presented in Table
3. The modeled receiver locations and 66 dBA (NAC B) noise contours for each alternative are
shown in Figure 8. Because difference between existing and no-action will only involve the
restriping of one lane, which does not affect the overall noise environment, the contour lines for
these two alternatives are the same. The specific noise model results for each receiver and
alternative are presented in Table 4.

                                                Table 3
                                      Section 1 General Contours
                                          Contour line distance from edge of pavement (feet)1
              Alternative
                                               66 dBA (NAC B)                     71 dBA (NAC C)
                                     Primarily on existing barrier
      Existing                       except for a small area on the              On existing barrier
                                     north and south where it is 125
                                     Primarily on existing barrier
      No-Action                      except for a small area on the              On existing barrier
                                     north and south where it is 180
      1
        Distances shown are for general comparison purposes and represent an average location of a contour
      line.




14                                                                                             November 2008
I-70 East Draft Environmental Impact Statement                                 Traffic Noise Technical Report


                                               Table 4
                                    Section 1 Noise Model Results
                                           2030                 2030 Build Alternatives
            Receiver     Existing
                                         No-Action              Build               Change*
            Globeville
                1          62.8             62.8                 63.4                 0.6
                2          62.5             62.5                 63.0                 0.5
                3          63.4             63.4                 64.1                 0.7
                4          63.2             63.2                 63.7                 0.5
                5          65.9             65.9                 66.6                 0.7
                6          67.1             67.1                 67.7                 0.6
                7          68.1             68.1                 68.7                 0.6
                8          67.0             67.0                 67.5                 0.5
                9          65.8             65.8                 66.3                 0.5
                10         65.8             65.8                 66.3                 0.5
                11         67.2             67.2                 67.5                 0.3
                12         67.4             67.4                 67.6                 0.2
                13         65.7             65.7                 66.1                 0.4
                14         64.9             64.9                 65.1                 0.2
                15         65.7             65.7                 66.2                 0.5
                16         63.9             63.9                 64.3                 0.4
                17         64.4             64.4                 64.9                 0.5
                18         63.9             63.9                 64.3                 0.4
                19         63.1             63.1                 63.5                 0.4
                20         65.3             65.3                 65.7                 0.4
                21         67.0             67.0                 67.3                 0.3
                22         65.7             65.7                 66.1                 0.4
                23         65.3             65.3                 65.7                 0.4
                24         65.4             65.4                 66.0                 0.6
                26         64.7             64.7                 65.0                 0.3
                27         64.7             64.7                 65.1                 0.4
                28         65.0             65.0                 65.4                 0.4
                29         65.9             65.9                 66.2                 0.3
                30         66.1             66.1                 66.4                 0.3
           Note: All noise readings are shown as dBA. Bold indicates impacted receivers at 66 dBA
           or above for any of the build alternatives.
           *Change in dB compared to existing conditions




November 2008                                                                                             15
Traffic Noise Technical Report                     I-70 East Draft Environmental Impact Statement


                                           Figure 8
                       Section 1 Receiver Locations and Noise Contours




6.2.2 Section 2 – Brighton Boulevard to Colorado Boulevard
Section 2 includes the Elyria, Swansea, Cole, Clayton, and Northeast Park Hill neighborhoods.
All build alternatives affect the noise environment for these communities. The general NAC B
and NAC C contour distances from edge of pavement are shown in Table 5. The modeled
receiver locations and 66 dBA (NAC B) noise contours for each alternative are shown in Figure
9. The specific noise model results for each receiver and alternative are shown in Table 6.




16                                                                               November 2008
              I-70 East Draft Environmental Impact Statement                                           Traffic Noise Technical Report


                                                                  Table 5
                                                        Section 2 General Contours
                                                               Contour line distance from edge of pavement
                                      Alternative                                 (feet)1
                                                                66 dBA (NAC B)                      71 dBA (NAC C)
                                Existing                         325 – 375                150 – 200
                                No-Action                       325 – 375                 150 – 200
                                1 and 3 (shifts north
                                                                450 – 500                 150 – 200
                                and south)
                                4 and 6 (western and
                                                                400 – 450                 150 – 200
                                eastern connections)
                                46th Avenue                         75                       N/A
                              1
                                Distances shown are for general comparison purposes and represent an average location of
                              a contour line.


                                                                 Table 6
                                                      Section 2 Noise Model Results

                                 No-Action                                             2030 Build Alternatives
   Receiver


                   Existing




                                 Alternative                        Alternative 1 or 3                           Alternative 4 or 6
                                                            North                      South                   West                 East
                              North      South                            *                        *                    *
                                                    Build      Change          Build       Change      Build     Change     Build     Change*
Elyria and Swansea North of I-70
  N21      66.7      66.4       67.4      69.2       2.5         68.8          2.1                X                    X
   N3      74.6      74.5       74.7      75.2       0.7         75.0          0.3        74.6         0.0             X
   N4      67.5      67.6       67.7      70.3       2.7         69.2          1.5        67.4        -0.1      71.1        3.6
   N5      65.7      66.0       65.8      68.7       2.7         67.6          1.8        65.5        -0.2      69.0        3.3
   N6      66.7      67.4       66.7      70.2       2.8         68.5          1.8        64.7        -2.0      67.5        0.8
   N7      63.6      63.9       63.7      66.5       2.6         65.5          1.8        63.9        0.3       68.0        4.4
   N8      72.5       X         72.1             X               73.3          1.2        66.7        -5.8      69.9       -2.6
   N9      69.9      71.6       69.6             X               71.0          1.4        64.7        -5.2      67.6       -2.3
  N10      68.5      69.8       68.3             X               69.8          1.5        63.7        -4.8      66.4       -2.1
  N11      67.6      68.7       67.5      71.9       3.2         69.0          1.5        63.2        -4.4      66.1       -1.5
  N12      66.7      67.6       66.6      70.6       3.0         68.2          1.6        62.8        -3.9      65.3       -1.4
  N13      65.6      66.4       65.5      69.2       2.8         67.2          1.7        62.5        -3.1      65.2       -0.4
  N14      64.7      65.4       64.7      68.2       2.8         66.4          1.7        62.1        -2.6      65.2       0.5
  N15      64.1      64.7       64.1      67.4       2.7         65.8          1.7        62.3        -1.8      64.7        0.6
  N16      60.6      60.4       60.9      63.3       2.9         62.7          1.8        68.5         7.9             X
  N17      61.2      61.1       61.4      63.9       2.8         63.2          1.8        65.6        4.4       72.5       11.3
  N18      59.9      60.0       60.1      62.8       2.8         62.0          1.9        63.9        4.0       68.9        9.0
  N19      59.4      59.6       59.6      62.4       2.8         61.5          1.9        63.1        3.7       67.4        8.0
  N20      57.9      58.0       58.1      60.9       2.9         60.1          2.0        63.8        5.9       68.5       10.6
  N21      57.8      57.9       58.0      60.8       2.9         59.9          1.9        62.6        4.8       66.2        8.4
Note: All noise readings are shown as dBA. Bold indicates impacted receivers at 66 dBA or above for any of the build or No-
Action Alternatives.
*Change in dB compared to existing conditions
1. The existing dBA level for receiver N12 was used as a surrogate for receiver N2 due to their equivalent distance from I-70.
2. The existing dBA level for receiver N22 was used as a surrogate ambient noise level for receivers RA41 through RA51.


              November 2008                                                                                                           17
              Traffic Noise Technical Report                                  I-70 East Draft Environmental Impact Statement


                                                            Table 6
                                                 Section 2 Noise Model Results

                                No-Action                                         2030 Build Alternatives
   Receiver


                   Existing


                                Alternative                    Alternative 1 or 3                           Alternative 4 or 6
                                                       North                      South                   West                  East
                              North    South
                                               Build        Change*       Build       Change*     Build     Change*     Build    Change*
 N22      56.5   56.6      56.8                59.5            2.9         58.8           2.0     64.2           7.7    69.0       12.5
 N23      70.9    X        70.3                         X                  70.1           -0.2    62.5           -8.4   62.5       -8.4
 N24      68.9   70.6      68.5                74.5            3.9         68.8            0.3    60.6           -8.3   60.6       -8.3
 N25      70.0   71.4      69.2                         X                  69.8            0.6    62.1           -7.9   62.1       -7.9
 N26      65.9   68.5      67.1                73.5            5.0         68.0            0.9    59.8           -6.1   59.8       -6.1
 N27      64.9   67.0      65.8                71.3            4.3         66.9            1.1    58.4           -6.5   58.4       -6.5
 N28      73.5    X        72.0                         X                  72.1            0.1    65.5           -8.0   65.5       -8.0
 N29      70.4         X                                X                  70.4                   62.6           -7.8   62.6       -7.8
 N30      74.3    X        73.4                         X                  73.7           0.3     66.3           -8.0   66.3       -8.0
 N31      71.3   73.2      70.8                         X                  71.2           0.4     63.5           -7.8   63.5       -7.8
 N32      66.2   69.8      68.3                         X                  69.1           0.8     61.0           -5.2   61.0       -5.2
 N33      62.8   64.7      63.9                68.7            4.0         65.3           1.4     56.7           -6.1   56.7       -6.1
 N34      64.6   67.1      66.1                71.8            4.7         67.1           1.0     59.0           -5.6   59.0       -5.6
 N35      63.5   65.6      64.7                69.6            4.0         66.0           1.3     57.8           -5.7   57.8       -5.7
 N36      70.6   72.4      70.4                         X                  70.5           0.1     63.0           -7.6   63.0       -7.6
 N37      66.4   70.2      68.7                         X                  69.2           0.5     61.5           -4.9   61.5       -4.9
 N38      65.6   68.6      67.4                74.4            5.8         68.1           0.7     60.3           -5.3   60.3       -5.3
 N39      66.4   68.8      67.7                         X                  68.0           0.3     61.1           -5.3   61.1       -5.3
Elyria and Swansea South of I-70
   S2      63.0      76.0        X        74.8       -1.2                 X                       X                     X
   S3      67.0      72.7        X        72.8       0.1                  X               66.5        -0.5      66.5       -0.5
   S4      67.6      71.2        X        71.7       0.5                  X               64.7        -2.9      64.7       -2.9
   S5      67.3      70.1       72.5      70.9       0.8                  X               63.3        -4.0      63.3       -4.0
   S6      66.4      67.6       69.1      68.9       1.3         74.8          5.7        60.5        -5.9      60.5       -5.9
   S7      64.5      65.2       66.2      66.9       1.7         70.6          4.4        57.9        -6.6      57.9       -6.6
   S8      63.9      64.3       65.2      66.1       1.8         69.3          4.1        57.0        -6.9       57        -6.9
   S9      63.3      63.7       64.5      65.5       1.8         68.4          3.9        56.3        -7.0      56.3       -7.0
  S10      63.0      63.3       64.1      65.2       1.9         67.9          3.8        55.9        -7.1      55.9       -7.1
  S11      61.7      61.9       62.5      63.8       1.9         66.0          3.5        54.5        -7.2      54.5       -7.2
  S12      61.0      61.1       61.6      63.1        2.0        65.0          3.4        53.7        -7.3      53.7       -7.3
  S13      64.7      65.3       66.2      67.2       1.9                  X               58.1        -6.6      58.1       -6.6
  S14      65.1       X          X               X                        X               69.1         4.0      69.1        4.0
  S15      67.7      72.2        X               X                        X               65.5        -2.2      65.5       -2.2
  S16      67.4      70.2       72.4      71.9        1.7                 X               63.2        -4.2      63.2       -4.2
  S17      67.2      68.9       70.6      70.6        1.7                 X               61.8        -5.4      61.8       -5.4
  S18      65.0      65.8       66.6      67.3       1.5         71.5          4.9        59.1        -5.9      59.1       -5.9
  S19      64.5      65.1       65.8      66.6       1.5         70.1          4.3        58.5        -6.0      58.5       -6.0
  S20      64.1      64.6       65.2      66.2       1.6         69.4          4.2        58.2        -5.9      58.2       -5.9
Note: All noise readings are shown as dBA. Bold indicates impacted receivers at 66 dBA or above for any of the build or No-
Action Alternatives.
*Change in dB compared to existing conditions
1. The existing dBA level for receiver N12 was used as a surrogate for receiver N2 due to their equivalent distance from I-70.
2. The existing dBA level for receiver N22 was used as a surrogate ambient noise level for receivers RA41 through RA51.


              18                                                                                                    November 2008
              I-70 East Draft Environmental Impact Statement                                      Traffic Noise Technical Report


                                                            Table 6
                                                 Section 2 Noise Model Results

                                No-Action                                         2030 Build Alternatives
   Receiver


                   Existing


                                Alternative                    Alternative 1 or 3                           Alternative 4 or 6
                                                       North                      South                   West                  East
                              North    South
                                               Build      Change*         Build         Change*   Build     Change*     Build    Change*
  S21     63.6                64.0      64.5   65.5            1.5         68.5           4.0     57.7           -5.9   57.7       -5.9
  S22     62.0                62.2      62.5   63.8            1.6         66.0           3.5     56.4           -5.6   56.4       -5.6
  S23     61.6                61.7      61.9   63.3             1.6        65.3           3.4     56.0           -5.6   56.0       -5.6
  S24     73.0                73.1      68.2   68.3            -4.8        73.1           4.9     71.6           -1.4   71.6       -1.4
  S25     69.3                70.2      70.3   69.2            -1.0                 X             64.7           -4.6   64.7       -4.6
  S26     65.0                66.3      66.7   67.1             0.8        71.4           4.7     60.5           -4.5   60.5       -4.5
  S27     64.3                65.6      65.9   66.5             0.9        70.2           4.3     60.2           -4.1   60.2       -4.1
  S28     63.7                64.8      64.9   65.8            1.0         69.0           4.1     59.8           -3.9   59.8       -3.9
  S29     62.9                64.0      63.9   65.0            1.0         67.8           3.9     59.3           -3.6   59.3       -3.6
  S30     62.2                63.2      62.9   64.2            1.0         66.6           3.7     58.8           -3.4   58.8       -3.4
  S31     61.5                62.5      62.0   63.4             0.9        65.7           3.7     58.3           -3.2   58.3       -3.2
  S32     67.6                71.0      73.0   71.5             0.5                 X             63.5           -4.1   63.5       -4.1
I-70 Realignment
 RA412 59.9          59.9       59.9      59.9        0          59.9           0          73        13.1        73        13.1
 RA42      59.9      59.9       59.9      59.9        0          59.9           0         71.2       11.3       71.2       11.3
 RA43      59.9      59.9       59.9      59.9        0          59.9           0         70.1       10.2       70.1       10.2
 RA44      59.9      59.9       59.9      59.9        0          59.9           0         67.3        7.4       67.3       7.4
 RA45      59.9      59.9       59.9      59.9        0          59.9           0          65         5.1        65        5.1
 RA46      59.9      59.9       59.9      59.9        0          59.9           0         67.8        7.9       67.8       7.9
 RA47      59.9      59.9       59.9      59.9        0          59.9           0         62.5        2.6       62.5       2.6
 RA48      59.9      59.9       59.9      59.9        0          59.9           0         65.3        5.4       65.3       5.4
 RA49      59.9      59.9       59.9      59.9        0          59.9           0         63.8        3.9       63.8       3.9
 RA50      59.9      59.9       59.9      59.9        0          59.9           0         64.4        4.5       64.4       4.5
 RA51      59.9      59.9       59.9      59.9        0          59.9           0         63.1        3.2       63.1       3.2
Note: All noise readings are shown as dBA. Bold indicates impacted receivers at 66 dBA or above for any of the build or No-
Action Alternatives.
* Change in dB compared to existing conditions
1. The existing dBA level for receiver N12 was used as a surrogate for receiver N2 due to their equivalent distance from I-70.
2. The existing dBA level for receiver N22 was used as a surrogate ambient noise level for receivers RA41 through RA51.




              November 2008                                                                                                       19
Traffic Noise Technical Report                 I-70 East Draft Environmental Impact Statement


                                         Figure 9
           Section 2 Existing Alignment Receiver Locations and Noise Contours




20                                                                           November 2008
I-70 East Draft Environmental Impact Statement                                Traffic Noise Technical Report


                                         Figure 10
                Section 2 Realignment Receiver Locations and Noise Contours




6.2.3 Section 3 – Colorado Boulevard to I-270
There are very few NAC B sites in Section 3 along the existing I-70 alignment as most of the
sites in this section fall under the NAC C category. However, the realignment along I-270 does
include the Commerce City neighborhood between Quebec Street and 56th Avenue. The general
NAC B and NAC C contour distances from edge of pavement are presented in Table 7. The
modeled receiver locations and 66 dBA (NAC B) noise contours for each alternative are shown
in Figure 11 and the specific noise model results for each receiver and alternative are presented
in Table 8.

                                               Table 7
                                     Section 3 General Contours
                                                       Contour line distance from edge of
                       Alternative                              pavement (feet)1
                                                     66 dBA (NAC B)            71 dBA (NAC C)
           Existing                                      225 – 275                 100 – 150
           No-Action                                     225 – 275                 100 – 150
           1 and 3 (shifts north and south)              450 – 500                 150 – 200
           4 (western and eastern connections)           500 – 550                 150 – 200
           6 (western and eastern connections)           525 – 575                 150 – 200
       1
        Distances are shown for general comparison purposes and represent an average location of a
       contour line.


November 2008                                                                                            21
      Traffic Noise Technical Report                                          I-70 East Draft Environmental Impact Statement


                                                                 Table 8
                                                         Section 3 Model Results

                                                                    2030 Build Alternatives
Receiver




                       2030 No-
            Existing


                        Action
                                    Alternative 1            Alternative 3             Alternative 4           Alternative 6
                                                     *                        *                          *                       *
                                  Build    Change         Build      Change         Build      Change        Build    Change

Northeast Park Hill
N4         62.2        62.2       63.6         1.4         64.5         2.3          63.3         1.1         62.8        0.6
N5         62.1        62.1       70.2         8.1         70.7         8.6          69.9         7.8         69.0        6.9
N6         62.9        62.9       66.5        3.6          66.7         3.8          68.0         5.1         68.2        5.3
S3         70.0        70.0       74.2        4.2          75.2         5.2          66.9         -3.1        66.8        -3.2
S4         65.6        65.6       69.5        3.9          71.2         5.6          67.9         2.3         65.5        -0.1
S5         66.9        66.9       70.7        3.8          72.1         5.2          68.9         2.0         68.9        2.0
Commerce City
 1         68.1        68.1       68.1         0           68.1          0           73.6         5.5         74.6        6.5
 2         69.2        69.2       69.2         0           69.2          0           74.9         5.7         76.3        7.1
 3         64.9        64.9       64.9         0           64.9          0           70.2         5.3         70.7        5.8
 4         70.4        70.4       70.4         0           70.4          0           76.2         5.8         78.3        7.9
 5         68.0        68.0       68.0         0           68.0          0           73.2         5.2         74.3        6.3
 6         67.6        67.6       67.6         0           67.6          0           72.7         5.1         73.6        6.0
 7         63.7        63.7       63.7         0           63.7          0           68.7         5.0         69.0        5.3
 8         62.5        62.5       62.5         0           62.5          0           67.5         5.0         67.8        5.3
 9         61.4        61.4       61.4         0           61.4          0           66.4         5.0         66.5        5.1
10         66.9        66.9       66.9         0           66.9          0           72.0         5.1         72.7        5.8
11         63.9        63.9       63.9         0           63.9          0           68.8         4.9         69.0        5.1
12         65.3        65.3       65.3         0           65.3          0           70.2         4.9         70.4        5.1
13         62.5        62.5       62.5         0           62.5          0           67.3         4.8         67.6        5.1
14         68.3        68.3       68.3         0           68.3          0           72.9         4.6         74.1        5.8
15         64.5        64.5       64.5         0           64.5          0           69.3         4.8         69.7        5.2
16         62.9        62.9       62.9         0           62.9          0           67.7         4.8         68.1        5.2
17         68.8        68.8       68.8         0           68.8          0           73.4         4.6         74.5        5.7
18         67.9        67.9       67.9         0           67.9          0           72.7         4.8         73.3        5.4
19         64.1        64.1       64.1         0           64.1          0           69.1          5          69.3        5.2
20         68.6        68.6       68.6         0           68.6          0           73.8         5.2         74.1        5.5
23         63.3        63.3       63.3         0           63.3          0           74.3         11          74.5        11.2
Note: All noise readings are shown as dBA. Bold indicates impacted receivers at 66 dBA or above for any of the build
alternatives.
* Change in dB compared to existing conditions




      22                                                                                                     November 2008
I-70 East Draft Environmental Impact Statement                                      Traffic Noise Technical Report


                                                Figure 11
                            Section 3 Receiver Locations and Noise Contours




6.2.4 Section 4 – I-270 to I-225
Section 4 includes the noise sensitive areas of the west portion of the Montbello neighborhood
north of I-70/I-225 and the Sand Creek Trail adjacent to the Stapleton redevelopment site which
does not have NAC B sensitive receivers proposed to be located adjacent to I-70. The majority of
the receivers in Section 4 are commercial (NAC C) category.

                                                    Table 9
                                          Section 4 General Contours
                                         Contour line distance from edge of pavement (feet)1
        Alternative
                                        66 dBA (NAC B)                               71 dBA (NAC C)
                            350 – 400 and on existing barrier in the     100 – 150 and on existing barrier in the
    Existing
                                        Montbello area                              Montbello area
                            350 – 400 and on existing barrier in the     100 – 150 and on the existing barrier in
    No-Action
                                        Montbello area                            the Montbello area
                              500 – 550 and Approximately 150 –
                                                                         150 – 200 and on the existing barrier in
    1 and 4 (all options)    200 beyond the existing barrier in the
                                                                                  the Montbello area
                                        Montbello area
                             550 – 600 and 175 – 225 beyond the          150 – 200 and on beyond the existing
    3 and 6 (all options)
                             existing barrier in the Montbello area          barrier in the Montbello area
1
    Distances shown are for general comparison purposes and represent an average location of a contour line.




November 2008                                                                                                  23
Traffic Noise Technical Report                               I-70 East Draft Environmental Impact Statement


                                               Table 10
                                    Section 4 Noise Model Results

                                                                 2030 Build Alternatives
                                   2030 No-
      Receiver      Existing                          Alternative 1 or 4             Alternative 3 or 6
                                    Action
                                                    Build         Change*          Build         Change*

     Montbello
          6            62.5           62.5           64.4            1.9            64.4            1.9
          7            62.4           62.4           64.6            2.2            64.6            2.2
          8            62.0           62.0           65.6            3.6            65.6            3.6
          9            63.0           63.0           64.6            1.6            64.6            1.6
         10            63.6           63.6           65.1            1.5            65.1            1.5
         11            63.9           63.9           65.3            1.4            65.3            1.4
         12            64.2           64.2           65.6            1.4            65.6            1.4
         13            64.2           64.2           65.6            1.4            65.6            1.4
         14            64.4           64.4           65.9            1.5            65.9            1.5
         15            64.4           64.4           66.6            2.2            66.6            2.2
         16            65.0           65.0           66.9            1.9            66.9            1.9
         17            65.2           65.2           66.9            1.7            66.9            1.7
         18            65.3           65.3           66.9            1.6            66.9            1.6
         19            65.7           65.7           67.0            1.3            67.0            1.3
     Note: All noise readings are shown as dBA. Bold indicates impacted receivers at 66 dBA or above for
     any of the build alternatives.
     * Change in dB compared to existing conditions




24                                                                                              November 2008
I-70 East Draft Environmental Impact Statement                               Traffic Noise Technical Report


                                           Figure 12
                       Section 4 Receiver Locations and Noise Contours




6.2.5 Section 5 – I-225 to Tower Road
Section 5 includes the noise sensitive areas of the east portion of the Montbello neighborhood
and large lot residences south of I-70 and east of I-225. The general NAC B and NAC C contour
distances from edge of pavement are presented in Table 11. The modeled receiver locations and
66 dBA (NAC B) noise contours for each alternative are shown in Figure 13 and the specific
noise model results for each receiver and alternative are presented in Table 12.

                                              Table 11
                                     Section 5 General Contours
                                               Contour line distance from edge of
                      Alternative                       pavement (feet)1
                                             66 dBA (NAC B)            71 dBA (NAC C)
                Existing                         350 – 400                100 – 150
                No-Action                        350 – 400                100 – 150
                All Action Alternatives          450 – 500                150 – 200
                1
                 Distances shown are for general comparison purposes and represent an
                average location of a contour line




November 2008                                                                                           25
Traffic Noise Technical Report                               I-70 East Draft Environmental Impact Statement


                                               Table 12
                                    Section 5 Noise Model Results

                                                   2030 No-           2030 Build Alternatives
              Receiver           Existing
                                                    Action              Build           Change*
           Montbello
               MB 11               66.7               66.7              66.4              -0.3
               MB 12               66.4               66.4              66.6               0.2
               MB 13           63.7             63.7                    64.7               1.0
           Large lot of homes south of I-70 (Aurora)
                 R3                66.7               66.7              68.5               1.8
                 R4                66.4               66.4              68.1               1.7
                 R5                70.0               70.0              71.5               1.5
                 R16               63.8               63.8              65.5               1.7
                 R17               65.4               65.4              67.0               1.6
           Note: All noise readings are shown as dBA. Bold indicates impacted receivers at 66 dBA or
           above for any of the build alternatives.
           *Change in dB compared to existing conditions



                                           Figure 13
                       Section 5 Receiver Locations and Noise Contours




26                                                                                               November 2008
I-70 East Draft Environmental Impact Statement                         Traffic Noise Technical Report



7.0    MITIGATION
As stipulated by CDOT guidelines, noise abatement measures must be considered if the noise
level at a sensitive site that meets and or exceeds the noise abatement criteria. CDOT primarily
provides noise abatement for NAC B noise sensitive areas (e.g., picnic areas, recreation areas,
playgrounds, active sports areas, parks, residences, motels, hotels, schools, churches, libraries,
and hospitals). NAC C sensitive areas (e.g., developed lands, properties, or activities not
included in Categories A or B) are general commercial locations where visibility and access are
more important than outside noise levels. However, during the FEIS all areas will be reviewed
for potential noise concerns. Abatement was evaluated for five predominately NAC B locations:
    1. Globeville neighborhood north and south of I-70 in Section 1
    2. The Elyria and Swansea neighborhoods in Section 2 and along the western portion of the
        realignment
    3. The Commerce City neighborhood in Section 3 of the realignment
    4. Montbello neighborhood north of the I-225/I-70 interchange in Sections 4 and 5
    5. Single family homes south of I-70 and east of I-225 in Section 5

Noise abatement was not developed for the Sand Creek Trail per discussions with the trail
manager because of the heights required for barriers on top of the already elevated roadway and
the desire to maintain views. Further discussions will take place during development of the FEIS.
Several scattered hotels in the corridor were also not considered for abatement at this time, but
will be analyzed in more detail in the FEIS.

7.1    MITIGATION STRATEGIES
Abatement measures considered include traffic system management techniques, alignment
modifications, property acquisition, land use controls, and noise barriers.

Traffic System Management
Traffic system management techniques that limit motor vehicle speeds and reduce traffic
volumes can be used to abate traffic noise. I-70 will remain a major thoroughfare supporting
intrastate and interstate commerce, and speed limits will not be reduced. However, the
realignment option would likely cause a substantial reduction in noise effects by relocating
mainline I-70 out of the Elyria and Swansea neighborhoods. However, traffic noise in areas
adjacent to the realignment areas will likely increase.

Alignment Modifications
Alignment modification involves orienting and/or siting the roadway at sufficient distances from
the noise sensitive areas so as to minimize traffic noise. Alternative alignments for I-70 are still
under consideration. The realignment alternative would likely reduce noise levels for most of the
residents in the Elyria and Swansea neighborhoods. However, traffic noise in areas adjacent to
the realignment areas will likely increase.

Property Acquisition
Property acquisition programs to provide noise buffer zones are not feasible due to the limited
availability and high cost of vacant land in proximity to noise sensitive sites.




November 2008                                                                                     27
Traffic Noise Technical Report                         I-70 East Draft Environmental Impact Statement


Land Use Controls
Land use controls can be used to minimize noise sensitive sites that may be affected by traffic
noise. Local planning officials should use the noise contour information and development site
plans to minimize the effects of traffic noise on proposed land uses that would be considered
noise sensitive. This especially applies to the development in the Stapleton Area or along areas
of the build alternatives that could redevelop.

Noise Barriers
Noise barriers reduce noise levels by blocking the sound path between a roadway and noise
sensitive site and are considered only if they are feasible and reasonable. CDOT has developed
the Noise Abatement Determination form, included in Appendix B, to ensure consistent
evaluation of noise abatement statewide. Some factors used to determine feasible and reasonable
barriers include:
    • Noise barriers should have a continuous length with no breaks or gaps for driveways or
        walkways.
    • Effective noise mitigation should create an insertion loss (the difference in noise levels
        after mitigation and before mitigation) of 5 dBA or greater for at least one front-row
        receiver.
    • A goal of 10 dBA reduction was also analyzed and in most cases a 20-foot or higher
        barrier was required. Noise abatement must be economically reasonable. This means
        mitigation must meet financial standards for cost effectiveness. One criterion is the Cost
        Benefit Index. A reasonable cost benefit expectation for a barrier is $3,000-$3,750 per
        receiver, per dB reduction. A cost-benefit value of more than $4,000 per receiver, per dB
        reduction is considered unreasonable. It should be noted that this threshold in and of itself
        will not eliminate a location from consideration, as there are other reasonableness factors
        that are taken into account. Forms in Appendix B provide further clarification.

        A hypothetical example of this calculation is a 400 foot long 12 foot high barrier provides
        a 6 dBA benefit (insertion loss) to eight front-row homes that were projected to be
        impacted by 66 dBA or higher Leq. This wall also benefited eight second row homes that
        were not impacted by 66 dBA, but received a 3 dBA reduction in noise levels. The cost
        calculation for this would be as follows:
            o Barrier cost = 400-foot long x 12-foot high x $30 per square foot = $144,000 ($30
                is a unit cost specified in CDOT guidance is for computing the cost-benefit factor
                only and does not necessarily represent all of the costs that are incurred when
                constructing a noise barrier.)
            o dB per benefited receivers = 8 front-row x 6 dBA reduction + 8 second row
                receivers x 3 dBA = 72
            o Results in a cost benefit index of $2,000 per dB reduction per benefited receiver,
                which would be considered economically reasonable.
            o Wherever noise abatement is warranted and determined feasible, other factors
                such as community desires, adjacent land uses, land use stability, development
                existence, safety considerations, drainage issues, utility conflicts, maintenance
                requirements, vegetation/environmental effects, access, and construction will be
                considered.



28                                                                                   November 2008
I-70 East Draft Environmental Impact Statement                        Traffic Noise Technical Report


An analysis of barriers for a representative site within each residential area was conducted to
determine if it was feasible to provide a 5 dBA reduction for each alternative. Wall heights of 12,
14, 16, 18, and 20 feet were analyzed for each representative site. These walls were placed
between the roadway and receivers, on the shoulder of ramps, frontage roads, and mainline I-70.
These were representative situations to determine if noise reducing techniques could be effective.
A more detailed analysis will be conducted in the FEIS.

7.2    PROPOSED MITIGATION
Barriers were not evaluated for the entire length of the impacted residential communities in the
project area. As stated previously, representative barriers were analyzed to determine if barriers
up to 20 feet high could provide a minimum of 5 dBA in noise reduction and if preliminary
reasonableness could be established for noise mitigation. There are specific
commercial/industrial areas of the corridor which are expected to meet or exceed the NAC C 71
dBA criterion. Mitigation for commercial/industrial properties is not normally reasonable for a
number of factors including the desire for adequate access and visibility. NAC C properties will
be reviewed during the FEIS. Potential mitigation measures are described for each section
containing NAC B properties for the preferred alternative.

Section 1
A barrier analysis was conducted for the Globeville neighborhood on both sides of I-70. The
average residences in the Globeville neighborhood currently experience average noise levels just
below 66 dBA due to an existing 10-foot noise barrier. The 2030 alternative noise level for front-
row receivers will increase by less than 1 dBA to just over 66 dBA. Future barrier locations
would remain along the ramp shoulders and mainline of I-70. Based on the analysis, a 16 to 20
foot barrier would provide at least an additional 5 dBA reduction to first-row receivers over and
above the existing barrier benefit, which is required to be considered for mitigation. Barriers
provided a benefit to a minimum of 51 residences at a cost benefit index of $16,900. Retrofitting
the existing barriers to accommodate a possible 20-foot barrier would be a considerable
challenge structurally and cost prohibitive, so reconstruction of the existing noise barriers would
most likely be required. From this initial review, additional noise mitigation does not appear to
be feasible or reasonable at this time. However, additional analyses will be conducted and a final
abatement determination made in the FEIS. For more information on the abatement
determination please see the associated CDOT Noise Abatement form included in Appendix B.

Section 2
A barrier analysis was performed for all alternatives for the Elyria and Swansea neighborhoods
for both the existing and realignment alternatives. The barrier locations along the ramp shoulders
and the highway mainline were evaluated as shown in Figure 14 through Figure 17. Based on the
analysis, a range of barrier heights from 12 to 20 feet would provide at least 5 dBA reduction to
first-row receivers. Barriers provide a benefit to roughly 64 receivers for the realignment and
more than 260 receivers for the existing alignment at a cost benefit index ranging from $3,900 to
$6,000. From this initial review, noise mitigation appears to be feasible and reasonable because it
is either within or close to CDOT’s desired cost benefit index. Additional analyses will be
conducted and an abatement determination will made for the Preferred Alternative in the FEIS.
For more information on the abatement determination please see the associated CDOT Noise
Abatement form included in Appendix B.



November 2008                                                                                    29
Traffic Noise Technical Report                        I-70 East Draft Environmental Impact Statement


An analysis of 46th Avenue has not been conducted at this time awaiting further details on
potential road and alley closures that would be needed to develop a continuous noise wall.
Additional analysis will be conducted and an abatement determination will made if the
realignment alternative is selected as the Preferred Alternative in the FEIS.

An analysis of the area associated with RA41 – RA51 mixed use (industrial, commercial, and
residential) area has not been conducted for the DEIS. This is due to the level of analysis
required to address the varied land uses and residential concentrations in the area. Additional
analyses will be conducted and an abatement determination will made for the Preferred
Alternative in the FEIS.

                                          Figure 14
                 Section 2 Barriers – Realignment Alternatives 4 and 6 West




30                                                                                  November 2008
I-70 East Draft Environmental Impact Statement                  Traffic Noise Technical Report


                                         Figure 15
             Section 2 Barriers – Existing Alignment Alternatives 4 and 6 East




                                          Figure 16
             Section 2 Barriers – Existing Alignment Alternatives 1 and 3 North




November 2008                                                                              31
Traffic Noise Technical Report                        I-70 East Draft Environmental Impact Statement


                                          Figure 17
             Section 2 Barriers – Existing Alignment Alternatives 1 and 3 South




Section 3
A barrier analysis was performed for all alternatives impacting the Commerce City neighborhood
by the realignment of I-70. The barrier locations are proposed along the mainline of the realigned
I-70 as in Figure 18 and Figure 19. Based on the analysis, a range of barrier heights from 12 to
20 feet would provide at least 5 dBA reduction to first-row receivers. Barriers provided a benefit
to a minimum of 68 residences at a cost benefit index ranging from $4,700 to $5,500. From this
initial review, noise mitigation appears to be feasible and reasonable. Additional analysis will be
conducted and an abatement determination will made for the Preferred Alternative in the FEIS.
For more information on the abatement determination please see the associated CDOT Noise
Abatement form included in Appendix B.




32                                                                                  November 2008
I-70 East Draft Environmental Impact Statement                  Traffic Noise Technical Report


                                          Figure 18
            Section 3 Barriers – Existing Alignment Alternative 4 West and East




                                          Figure 19
            Section 3 Barriers – Existing Alignment Alternative 6 West and East




November 2008                                                                              33
Traffic Noise Technical Report                        I-70 East Draft Environmental Impact Statement


Section 4
A barrier analysis was conducted for all alternatives for the Montbello neighborhood north of the
I-225/I-70 interchange. This neighborhood currently has a 10-foot wall located along the
shoulder of the ramp from Peña Boulevard to Peoria Street. The barrier location along the
shoulder of the ramp was evaluated. With the existing 10-foot barrier and storage facility in
place, the future noise levels for first-row homes increased by roughly 1.5 dBA from upper 64
and 65 dBA to mid 66 dBA for most alternatives. Based on the analysis, a range of barrier
heights from 12 to 20 feet would not provide at least 5 dBA reduction to first-row receivers.
From this initial review, noise mitigation appears to not be feasible and reasonable. However,
additional analysis will be conducted and an abatement determination will made for the Preferred
Alternative in the FEIS. For more information on the abatement determination please see the
associated CDOT Noise Abatement form included in Appendix B.

Section 5
A barrier analysis was conducted for all alternatives for the eastern half of the Montbello
neighborhood north of I-70 and the single family homes east of Chambers Road and south of I-
70 and east of I-225.

A barrier along the Peoria Street on ramp for the Montbello neighborhood was evaluated. Based
on the analysis, a range of barrier heights from 12 to 20 feet would not provide at least 5 dBA
reduction to first-row receivers in the Montbello neighborhood. With the existing 10-foot barrier
and storage facility in place, the future noise levels for first-row homes increased by roughly 1.5
dBA from upper 64 and 65 dBA to mid 66 dBA for most alternatives. Based on the analysis, a
range of barrier heights from 12 to 20 feet would not provide at least 5 dBA reduction to first-
row receivers. From this initial review, noise mitigation appears to not be feasible and
reasonable. However, additional analysis will be conducted and an abatement determination will
made for the Preferred Alternative in the FEIS. For more information on this recommendation
please see the associated CDOT Noise Abatement form included in Appendix B.

A barrier along the Chambers Road on-ramp and mainline shoulders of I-70 for the single-family
homes south of I-70 was also evaluated. Based on the analysis, a range of barrier heights from 12
to 20 feet would provide at least 5 dBA reduction to first-row receivers for the single family
homes south of I-70. This barrier provided a benefit to a minimum of eight residences at a cost
benefit index of $22,800 per receptor. From this initial review, noise mitigation appears to be
feasible. However, the economic reasonableness of providing mitigations is questionable.
Additional analysis will be conducted and an abatement determination will made for the
Preferred Alternative in the FEIS. For more information on the abatement determination please
see the associated CDOT Noise Abatement form included in Appendix B.

7.3     CONCLUSIONS AND RECOMMENDATIONS
Noise barriers were considered for NAC B sites in Sections 1, 2, 3, 4, and 5 because the
projected 2030 noise levels exceeded the 66 dBA criterion. The representative noise barriers for
neighborhoods in Sections 2 and 3 appear to meet the criteria for feasible and reasonable, as
described above. Barriers in Section 1 for the Globeville neighborhood, Sections 4 and 5 for the
Montbello neighborhood, and Section 5 for the large lot neighborhood south of I-70 and east of
I-225 do not appear to meet the criteria for feasible and reasonable. However, additional analysis
will be conducted for all sections and a final abatement determination made in the FEIS.


34                                                                                  November 2008
I-70 East Draft Environmental Impact Statement                         Traffic Noise Technical Report


7.4    CONSTRUCTION NOISE
Construction noise would present the potential for short-term impacts to those receptors located
along the corridor and along designated construction access routes. It is anticipated that a portion
of the construction would occur at night to minimize traffic disruption. The primary source of
construction noise is expected to be diesel-powered equipment such as trucks and earth moving
equipment and construction activities such as demo hammers on trackhoes, rubble load outs,
tailgate and bucket bang..

Section 36-6(b)(7) of the Denver Code, from the Department of Environmental Health, states
that the maximum permissible sound pressure levels specified in the code do not apply to sounds
emitted from construction equipment operated between the hours of 7:00 a.m. and 9:00 p.m.
Between 9:00 p.m. and 10:00p.m., operation of construction equipment may not exceed the
maximum sound pressure levels specified as:
    • 55 dBA at the property line of a residential premise
    • 65 dBA at the property line of a commercial premise
    • 80 dBA at the property line of an industrial premise
    • 75 dBA anywhere on a public premise

However, operation of construction equipment between the hours of 10:00 p.m. and 7:00 a.m.
may not exceed the maximum sound pressure levels specified as:
   • 50 dB at the property line of a residential premise
   • 60 dB at the property line of a commercial premise
   • 75 dB at the property line of an industrial premise
   • 70 dB anywhere on a public premise

Section 146- 1964(b)(3) of the Aurora City Code, obtained from the website of the planning
department explains that construction work for an approved development plan shall be subject to
the maximum permissible sound levels specified as follows:
    • 80 dB between the hours of 7:00 a.m. and 9:00 p.m. of the same day
    • 75 dB between the hours of 9:00 p.m. and 7:00 a.m. of the next day

According to Building Division of the Development Services Office, the unincorporated sections
of Arapahoe County do not have a noise ordinance pertaining to construction.

Pile driving is expected to be the loudest single construction operation. Piles would be required
at most major bridge installations. The typical noise level produced by pile driving at a distance
of 50 feet exceeds the maximum allowable sound levels for nighttime construction listed above.
Other construction activities may also exceed these requirements. The majority of noise
receptors are located greater than 50 feet from areas where pile driving or other high-noise
activities are expected. Noise impacts are expected to occur only in isolated areas along the
project corridor.

Construction Mitigation
Construction noise impacts to local businesses will be presented to the public as part of the
design public involvement program that will occur after completion of the FEIS and Record of
Decision. Public suggestions will be incorporated into the mitigation plan, where appropriate. By
contract agreement, each construction contractor will be required to submit a work plan outlining

November 2008                                                                                     35
Traffic Noise Technical Report                       I-70 East Draft Environmental Impact Statement


work schedules and intended mitigation measures prior to initiating construction. The effective
control of highway construction noise can be achieved by considering:
   • Alternative design options
   • Mitigation at the source
   • Mitigation along the path
   • Mitigation at the receiver

The following measures will be used to mitigate noise impacts:
   • Construct permanent sound barriers prior to roadway construction, where possible from a
       construction staging standpoint
   • Use noise blankets on equipment and quiet-use generators
   • Minimize construction duration in residential areas, as much as possible
   • Minimize nighttime activities in residential areas, as much as possible
   • Re-route truck traffic away from residential streets, where possible
   • Combine noisy operations to occur in the same time period
   • Use alternative construction methods, such as sonic or vibratory pile driving in sensitive
       areas
   • Conduct pile driving and other high-noise activities during daytime construction, where
       possible

For more information on construction noise issues see FHWA’s Highway Construction Noise
Handbook (2006).

7.5     LOCAL AGENCY COORDINATION
Local government officials can promote compatibility between land development and highways
by ensuring that NAC B type development is restricted or limited within the projected 66 dBA
contours of major highways. Local officials can use the noise contour data to establish
compatible development of currently undeveloped parcels or compatible redevelopment in areas
where land use changes. NAC C sites should use this information to situate outdoor use areas
associated with office buildings and commercial centers away from the roadway.




36                                                                                 November 2008
I-70 East Draft Environmental Impact Statement                     Traffic Noise Technical Report


8.0    REFERENCES
Colorado Department of Transportation. (2002). Noise analysis and abatement guidelines.
       Denver: Author.

Council on Environmental Quality. (n.d.). Council on Environmental Quality regulations for
      implementing National Environmental Policy Act, part 1502: Environmental impact
      statement. 40 CFR § 1502.14. Washington, D.C.: U.S. Government Printing Office.

Federal Highway Administration. (1995). Highway traffic noise analysis and abatement policy
            and guidance. Washington, D.C.: Author.

Federal Highway Administration. (1996). Measurement of highway-related noise. Washington,
       D.C.: Author.

Federal Highway Administration. (1997). Procedures for abatement of highway traffic noise and
       construction noise, 23 CFR § 772.

National Environmental Policy Act of 1969, Pub. L. No. 91-190, 83 Stat. 852,
       42 USC § 4321-4327.

Transportation Research Board. (2000). Highway capacity manual. Washington, D.C.: National
      Academy of Sciences.

U.S. Department of Transportation, Research and Innovative Technology Administration.
       (2006). Federal Highway Administration Highway construction noise handbook.
       Cambridge, MA: Author.




November 2008                                                                                 37
Traffic Noise Technical Report                        I-70 East Draft Environmental Impact Statement




                                 This page intentionally left blank.




38                                                                                  November 2008
APPENDIX A
I-70 East Draft Environmental Impact Statement                                                                                                                                                      Traffic Noise Technical Report


                                                                                                                                                                                                                        Table A-1
                                                                                                                                                                                                               Monitoring Results
                                                                                                   Noise Measurements
                                                                                                    Distance                                                                        Validation
                                                                                                                                               ***Grade                  Train
              Location                      Date     Meter      *Time       Duration    Wind       from Road    Leq     **Meter Placement                 Land Use                  (Modeled -                 Comments
                                                                                                                                                  (Ft)                  Passbys
                                                                                                    or Tracks                                                                       Measured)
     46th Avenue/Grant Street (north                                                                                     5 Ft above 46th                                                            10 Ft wall, see stacks from
1    side of I-70)                       6/23/2004   Type 1   11:00-11:15    15 min    5 mph (s)     100 Ft     64.1          Avenue              4       Residential     N/A      62.7-64.1=-1.4   trucks
     46th Avenue/Grant Street (north                                                                                     5 Ft above 46th                                                            10 Ft wall, see stacks from
1    side of I-70)                       6/23/2004   Type 2   11:00-11:15    15 min    5 mph (s)     50 Ft      66.5          Avenue              4       Residential     N/A      62.1-66.5=-4.4   trucks
     46th Avenue/Grant Street (north                                                                                     5 Ft above 46th                                                            10 Ft wall, see stacks from
1    side of I-70)                       6/23/2004   Type 1   11:20-11:35    15 min    5 mph (s)     100 Ft     62.4          Avenue              4       Residential     N/A      62.2-62.4=-0.2   trucks
     46th Avenue/Grant Street (north                                                                                     5 Ft above 46th                                                            10 Ft wall, see stacks from
1    side of I-70)                       6/23/2004   Type 2   11:20-11:35    15 min    5 mph (s)     50 Ft      66.0          Avenue              4       Residential     N/A      61.8-66.0=-4.2   trucks
     42nd Avenue/Grant Street (south                                                                                     5 Ft above 42nd                                                            10 Ft wall, see stacks from
2    side of I-70)                       6/23/2004   Type 1   9:47-10:02     15 min    5 mph (s)     50 Ft      65.6          Avenue              2       Residential     N/A      62.7-65.6=-2.9   trucks
     42nd Avenue/Grant Street (south                                                                                     5 Ft above 42nd                                                            10 Ft wall, see stacks from
2    side of I-70)                       6/23/2004   Type 2   9:47-10:02     15 min    5 mph (s)     100 Ft     62.0          Avenue              2       Residential     N/A      62.8-62.0=0.8    trucks
     42nd Avenue/Grant Street (south                                                                                     5 Ft above 42nd                                                            10 Ft wall, see stacks from
2    side of I-70)                       6/23/2004   Type 1   10:30-10:45    15 min    5 mph (s)     50 Ft      65.9          Avenue              2       Residential     N/A      62.9-65.9=-3.0   trucks, vehicle idling near by
     42nd Avenue/Grant Street (south                                                                                     5 Ft above 42nd                                                            10 Ft wall, see stacks from
2    side of I-70)                       6/23/2004   Type 2   10:30-10:45    15 min    5 mph (s)     100 Ft     62.3          Avenue              2       Residential     N/A      63.0-62.3=0.7    trucks
     46th Avenue/Pennsylvania Street
3    (north side of I-70)                6/10/2004   Type 1    2:55-3:10     15 min    6 mph (n)     300 Ft     56.1    5 Ft above 46th Aven      4       Residential     N/A                       10 Ft wall, birds chirping
     46th Avenue/Pennsylvania Street                                                                                     5 Ft above 46th
3    (north side of I-70)                6/10/2004   Type 2    2:55-3:10     15 min    6 mph (n)     30 Ft      61.9          Avenue              4       Residential     N/A                       10 Ft wall, birds chirping
     46th Avenue/Pennsylvania Street                                                                                     5 Ft above 46th
3    (north side of I-70)                6/10/2004   Type 1    3:12-3:27     15 min    6 mph (n)     300 Ft     58.8          Avenue              4       Residential     N/A                       10 Ft wall, birds chirping
     46th Avenue/Pennsylvania Street                                                                                     5 Ft above 46th
3    (north side of I-70)                6/10/2004   Type 2    3:12-3:27     15 min    6 mph (n)     30 Ft      63.5          Avenue               4      Residential     N/A                       10 Ft wall, birds chirping
                                                                                                                                                 I-70
                                                                                                                         5 Ft above Sand       Mainline
4    South Platte River Trail            6/2/2004    Type 1    2:40-2:55     15 min     None         100 Ft     63.8        Creek Trail           20         Trail       None
                                                                                                                                                 I-70
                                                                                                                         5 Ft above Sand       Mainline
4    South Platte River Trail            6/2/2004    Type 1    2:56-3:11     15 min     None         100 Ft     64.0        Creek Trail           20         Trail      1 Train
                                                                                                                                                 I-70
                                                                                                                         5 Ft above Sand       Mainline
4    South Platte River Trail            6/2/2004    Type 1    3:18-3:33     15 min     None         799 Ft     62.0        Creek Trail           20         Trail      2 Trains                    Airplane
                                                                                                                                                 I-70
                                                                                                                         5 Ft above Sand       Mainline
4    South Platte River Trail            6/2/2004    Type 1    3:33-3:48     15 min     None         799 Ft     62.2        Creek Trail           20         Trail      1 Train                     People walking by
                                                                                                                                                 I-70
                                                                                                                                               Mainline
5    Globeville Landing Park             6/2/2004    Type 1    3:50-4:05     15 min     None         385 Ft     67.2      Middle of Park          20         Park       1 Train
                                                                                                                                                 I-70
                                                                                                                                               Mainline
5    Globeville Landing Park             6/2/2004    Type 1   4:07-4:22      15 min     None         385 Ft     66.2     Middle of Park           20        Park        1 Train
6    Blake Street/33rd Street            6/7/2004    Type 1   9:00-10:00     15 min     None         300 Ft     60.6     5 Ft above RR          Level     Residential   4 Trains                    2 trains were engine only
                                                                                                                         5 Ft above 28th
7    Welton Street/28th Street           6/25/2004   Type 1   10:37-11:41    1 hour     5 mph        25 Ft      66.5         Avenue             Level     Residential   8 Trains                    3 cars per train


November 2008                                                                                                                                                                                                                    A1
Traffic Noise Technical Report                                                                                                                                                 I-70 East Draft Environmental Impact Statement


                                                                                                                                                                                                                  Table A-1
                                                                                                                                                                                                         Monitoring Results
                                                                                                 Noise Measurements
                                                                                                  Distance                                                                       Validation
                                                                                                                                          ***Grade                   Train
              Location                   Date     Meter      *Time       Duration     Wind       from Road    Leq     **Meter Placement              Land Use                    (Modeled -               Comments
                                                                                                                                             (Ft)                   Passbys
                                                                                                  or Tracks                                                                      Measured)
                                                                                                                       5 Ft above 28th                                                          Metal grinder in use, cars with
7    Welton Street/28th Street        6/22/2004   Type 1    1:35-1:50     15 min      None         50 Ft      60.4         Avenue          Level     Residential    2 Trains                    loud music
                                                                                                                       5 Ft above 28th                                                          Metal grinder in use, cars with
7    Welton Street/28th Street        6/22/2004   Type 2    1:35-1:50     15 min      None         100 Ft     58.8         Avenue          Level     Residential    2 Trains                    loud music
                                                                                                                       5 Ft above 28th
7    Welton Street/28th Street        6/22/2004   Type 1    1:50-2:05     15 min      None         50 Ft      60.0         Avenue          Level     Residential    1 Train                     Cars with loud music
                                                                                                                       5 Ft above 28th
8    Welton Street/28th Street        6/22/2004   Type 2    1:50-2:05     15 min      None         100 Ft     57.2         Avenue          Level     Residential    1 Train                     Cars with loud music
                                                                                                                       5 Ft above 30th
9    Welton Street/30th Street        6/23/2004   Type 1    2:15-2:30     15 min      None         50 Ft      58.5         Avenue          Level     Residential      N/A                       Cars with loud music
                                                                                                                       5 Ft above 30th
9    Welton Street/30th Street        6/24/2004   Type 2    2:15-2:30     15 min      None         100 Ft     55.8         Avenue          Level     Residential      N/A                       Cars with loud music
                                                                                                                       5 Ft above 30th
9    Welton Street/30th Street        6/25/2004   Type 1    2:35-2:50     15 min      None         50 Ft      59.3         Avenue          Level     Residential      N/A                       Cars with loud music
                                                                                                                       5 Ft above 30th
9    Welton Street/30th Street        6/26/2004   Type 2    2:35-2:50     15 min      None         100 Ft     56.4         Avenue          Level     Residential      N/A                       Cars with loud music
                                                                                                                       5 Ft above 33rd               Residential/
10   Downing Street/33rd Street       6/7/2004    Type 1   10:30-10:45    15 min      None         30 Ft      63.7         Avenue          Level      Business        N/A
                                                                                                                       5 Ft above 33rd               Residential/
10   Downing Street/33rd Street       6/7/2004    Type 1   10:50-11:05    15 min      None         30 Ft      64.7         Avenue          Level      Business        N/A
     Bruce Randolph Avenue/Humboldt
11   Street                           6/30/2004   Type 1   10:00-10:15    15 min      None         50 Ft      61.1      5 Ft above BR      Level       School         N/A
     Bruce Randolph Avenue/Humboldt
11   Street                           6/30/2004   Type 1   10:20-10:35    15 min      None         50 Ft      61.8     5 Ft above BR       Level       School         N/A                       Helicopter, loud music
12   Brighton Blvd/52nd Avenue        6/30/2004   Type 1   12:35-12:50    15 min      None         50 Ft      59.7     5 Ft above RR       Level      Cemetery       None
12   Brighton Blvd/52nd Avenue        6/30/2004   Type 1   12:55-1:10     15 min      None         50 Ft      60.0     5 Ft above RR       Level      Cemetery       None
     Columbine Street/46th Avenue                                                     6 mph                            5 Ft above 47th
13   (Swansea Elem. School)           6/10/2004   Type 2   10:45-11:00    15 min       (nw)        613 Ft     64.9         Avenue           20         School         N/A      60.9-63.7=-2.8   Purina Conveyor
     Columbine Street/46th Avenue                                                     6 mph                            5 Ft above 46th
13   (Swansea Elem. School)           6/10/2004   Type 1   10:45-10:55    15 min       (nw)        185 Ft     65.4         Avenue           20         School         N/A      68.2-65.4=2.8    Purina Conveyor
     Columbine Street/46th Avenue                                                     6 mph                            5 Ft above 47th
13   (Swansea Elem. School)           6/10/2004   Type 2   11:07-11:22    15 min       (nw)        613 Ft     57.4         Avenue           20         School         N/A      59.4-59.4=0.0    Purina Conveyor
     Columbine Street/46th Avenue                                                     6 mph                            5 Ft above 46th
13   (Swansea Elem. School)           6/10/2004   Type 1   11:07-11:22    15 min       (nw)        185 Ft     65.2         Avenue           20         School         N/A      69.2-65.2=4.0    Purina Conveyor
     Columbine Street/46th Avenue
13   (Swansea Elem. School)           7/20/2004   Type 1   2PM – 2PM     24 hour       N/A         272 Ft     68.3       school roof         5        School          N/A                       Purina Conveyor
     Clayton Street/45th Avenue                                                                                        5 Ft above 45th               Park/Resid
15   (Dunham Park)                    6/10/2004   Type 1   11:52-12:07    15 min    5 mph (ne)     390 Ft     66.1         Avenue           20         ential         N/A      64.7-66.1=-1.4   Purina Conveyor, truck idling
     Clayton Street/45th Avenue                                                                                        5 Ft above 45th               Park/Resid
15   (Dunham Park)                    6/10/2004   Type 2   11:52-12:07    15 min    5 mph (ne)     453 Ft     64.0         Avenue           20         ential         N/A      64.6-64.0=0.6    Purina Conveyor
     Clayton Street/45th Avenue                                                                                        5 Ft above 45th               Park/Resid
15   (Dunham Park)                    6/10/2004   Type 1   12:08-12:23    15 min    5 mph (ne)     390 Ft     63.8         Avenue           20         ential         N/A      64.9-63.8=1.1    Purina Conveyor
     Clayton Street/45th Avenue                                                                                        5 Ft above 45th               Park/Resid
15   (Dunham Park)                    6/10/2004   Type 2   12:08-12:23    15 min    5 mph (ne)     415 Ft     62.2         Avenue           20         ential         N/A      63.7-62.2=1.5    Purina Conveyor



A2                                                                                                                                                                                                            November 2008
I-70 East Draft Environmental Impact Statement                                                                                                                                                      Traffic Noise Technical Report


                                                                                                                                                                                                                      Table A-1
                                                                                                                                                                                                             Monitoring Results
                                                                                                   Noise Measurements
                                                                                                    Distance                                                                        Validation
                                                                                                                                               ***Grade                   Train
              Location                      Date     Meter      *Time       Duration    Wind       from Road     Leq    **Meter Placement                 Land Use                  (Modeled -                Comments
                                                                                                                                                  (Ft)                   Passbys
                                                                                                    or Tracks                                                                       Measured)
                                                                                                                                                          Business/G
16   Colorado Blvd/41st Avenue           6/29/2004   Type 1    3:30-3:45     15 min    5 mph (n)      50 Ft      71.1           5 Ft            Level     olf Course       N/A                      Stop Light at 40th Avenue
     Smith Road (1/2 mile east of                                                                                        5 Ft above Smith
17   Colorado Blvd)                      6/25/2004   Type 1    1:05-2:05     1 hour    5 mph (e)     150 Ft      66.7          Road             Level     Residential     None
                                                                                                                                                          Residential/
18   MLK Blvd/Birch Street               6/30/2004   Type 1    9:05-9:20     15 min     None          50 Ft      66.4   5 Ft above MLK Blvd     Level        Park          N/A                      Helicopter, Bus Stop
                                                                                                                                                          Residential/
18   MLK Blvd/Birch Street               6/30/2004   Type 1    9:25-9:40     15 min     None          50 Ft      65.7   5 Ft above MLK Blvd     Level        Park          N/A
                                                                                                                          5 Ft above Sand
19   Sand Creek Trail (south of I-70)    6/9/2004    Type 1   9:55-10:10     15 min     None         100 Ft      72.1        Creek Trail         25          Trail         N/A     74.0-72.1=1.9
                                                                                                                          5 Ft above Sand
20   Sand Creek Trail (south of I-70)    6/9/2004    Type 2   9:55-10:10     15 min     5 mph        130 Ft      70.9        Creek Trail         25          Trail         N/A     71.1-70.9=0.2
                                                                                                                          5 Ft above Sand
19   Sand Creek Trail (south of I-70)    6/9/2004    Type 1   10:15-10:30    15 min     None         100 Ft      72.3        Creek Trail         25          Trail         N/A     74.4-72.3=2.1
                                                                                                                          5 Ft above Sand
20   Sand Creek Trail (south of I-70)    6/9/2004    Type 2   10:15-10:30    15 min     5 mph         130 Ft     71.0        Creek Trail         25          Trail         N/A     71.3-71.0=0.3
                                                                                        5 mph       55 Ft from
21   Peoria Street (north of I-70)       6/1/2004    Type 2    2:25-2:40     15 min      (nw)         ramp       67.2      5 Ft near pool        20          Hotel         N/A     67.4-67.2=0.2    20 Ft below interstate
                                                                                        5 mph      100 Ft from
21   Peoria Street (north of I-70)       6/1/2004    Type 1    2:25-2:40     15 min      (nw)         ramp       63.8     5 Ft near ramp         25          Hotel         N/A     61.8-63.8=-2.0   20 Ft below interstate
                                                                                        5 mph       55 Ft from
21   Peoria Street (north of I-70)       6/1/2004    Type 2    3:00-3:15     15 min      (nw)         ramp       68.0      5 Ft near pool        20          Hotel         N/A     67.4-68.0=-0.6   Jack hammer (3-4 db)
                                                                                        5 mph      100 Ft from
21   Peoria Street (north of I-70)       6/1/2004    Type 1    3:00-3:15     15 min      (nw)         ramp       64.9     5 Ft near ramp         25          Hotel         N/A     61.9-64.9=-3.0   20 Ft below interstate
     Northeast of I-70/I-225                                                                         491 from
22   Interchange                         6/9/2004    Type 1   11:00-11:15    15 min     5 mph         ramp       63.1      5 Ft near apts        15       Residential      N/A                      Georgia Pacific saws
     Northeast of I-70/I-225                                                                         491 from
22   Interchange                         6/9/2004    Type 2   11:00-11:15    15 min     5 mph         ramp       63.0      5 Ft near apts        15       Residential      N/A                      Georgia Pacific saws
     Northeast of I-70/I-225                                                                         491 from
22   Interchange                         6/9/2004    Type 1   11:25-11:40    15 min     5 mph         ramp       61.7      5 Ft near apts        15       Residential      N/A
     Northeast of I-70/I-225                                                                         491 from
22   Interchange                         6/9/2004    Type 2   11:25-11:40    15 min     5 mph         ramp       61.3      5 Ft near apts        15       Residential      N/A
     16000 East 40th Avenue (west of
23   DIA Storage)                        6/1/2004    Type 1    1:20-1:35     15 min      none        195 Ft      65.0       5 Ft on road        Level     Residential      N/A     61.9-65.0=-3.1   10 Ft Sound Wall
     16000 East 40th Avenue (west of
23   DIA Storage)                        6/1/2004    Type 2    1:20-1:35     15 min      none         75 Ft      63.2     5 Ft in vacant lot      5       Residential      N/A     60.1-63.2=-3.1   10 Ft Sound Wall
     16000 East 40th Avenue (west of
23   DIA Storage)                        6/1/2004    Type 1    1:45-2:00     15 min      none        195 Ft      65.5       5 Ft on road        Level     Residential      N/A     63.0-65.5=-2.5   10 Ft Sound Wall
     16000 East 40th Avenue (west of
23   DIA Storage)                        6/1/2004    Type 2    1:45-2:00     15 min     none          75 Ft      65.0     5 Ft in vacant lot      5       Residential      N/A     61.3-65.0=-3.7   10 Ft Sound Wall
     15100 East 40th Avenue (east of                                                   3-5 mph                                                            Hotel/cond
24   DIA Storage)                        6/1/2004    Type 2   11:40-11:55    15 min       (e)         75 Ft      72.6     5 Ft in vacant lot    Level         o            N/A     72.1-72.6=-0.5   None
     15100 East 40th Avenue (east of                                                   3-5 mph                                                            Hotel/cond
24   DIA Storage)                        6/1/2004    Type 1   11:40-11:55    15 min       (e)        100 Ft      71.5     5 Ft in vacant lot    Level         o            N/A     71.3-71.5=-0.2   None



November 2008                                                                                                                                                                                                                   A3
 Traffic Noise Technical Report                                                                                                                                                      I-70 East Draft Environmental Impact Statement


                                                                                                                                                                                                                        Table A-1
                                                                                                                                                                                                               Monitoring Results
                                                                                                     Noise Measurements
                                                                                                      Distance                                                                         Validation
                                                                                                                                                  ***Grade                  Train
               Location                     Date       Meter        *Time      Duration    Wind      from Road    Leq     **Meter Placement                  Land Use                  (Modeled -               Comments
                                                                                                                                                     (Ft)                  Passbys
                                                                                                      or Tracks                                                                        Measured)
      15100 East 40th Avenue (east of                                                     3-5 mph                                                            Hotel/cond
24    DIA Storage)                       6/1/2004      Type 2    12:00-12:15    15 min       (e)       75 Ft      72.1      5 Ft in vacant lot     Level         o           N/A     71.9-72.1=-0.2   Truck Horn
      15100 East 40th Avenue (east of                                                     3-5 mph                                                            Hotel/cond
24    DIA Storage)                       6/1/2004      Type1     12:00-12:15    15 min       (e)       100 Ft     70.6      5 Ft in vacant lot     Level         o           N/A     71.1-70.6=0.5    Truck Horn
      15100 East 40th Avenue (east of                                                                                                                        Hotel/cond
25    DIA Storage)                       6/29/2004     Type 1    11:40-11:55    15 min     None        384 Ft     60.1        5 Ft on road         Level         o           N/A                      Dog barking
                                                                                          3-5 mph
28    Kalispell Street/38th Avenue       6/1/2004      Type 1    10:30-10:45    15 min      (sw)       75 Ft      72.2    5 Ft above vacant lot    Level     Residential     N/A     72.0-72.2=-0.2   Lawn Mower
                                                                                          3-5 mph
27    Kalispell Street/38th Avenue       6/1/2004      Type 2    10:30-10:45    15 min      (sw)       100 Ft     70.2    5 Ft above vacant lot      -2      Residential     N/A     71.4-70.2=1.2    Lawn Mower
                                                                                          3-5 mph
28    Kalispell Street/38th Avenue       6/1/2004      Type 1    10:50-11:05    15 min      (sw)       75 Ft      73.1    5 Ft above vacant lot    Level     Residential     N/A     72.3-73.1=-0.8   Killdeer, Airplane
                                                                                          3-5 mph
27    Kalispell Street/38th Avenue       6/1/2004      Type 2    10:50-11:06    15 min      (sw)      100 Ft      71.0    5 Ft above vacant lot      -2      Residential     N/A     71.7-71.0=0.7    Killdeer, Airplane
                                                                                                     166' from
27    Kalispell Street/38th Avenue       6/29/2004     Type 1     1:45-2:00     15 min     5 mph       ramp       63.8    5 Ft above vacant lot    Level     Residential     N/A
                                                                    3PM-                             166' from                                                                                        Storm at 2:00 PM on 22nd
29    Kalispell Street/38th Avenue       7/21/2004     Type 1     12:30PM       24 hour      N/A       ramp       72.2    5 Ft above vacant lot    Level     Residential     N/A                      Avenue
30    Tower Road/51st Avenue             6/29/2004     Type 1    11:04-11:19    15 min     5 mph      100 Ft      57.3             5 Ft            Level     Residential     N/A
31    Tower Road/49th Avenue             6/9/2004      Type 1     9:05-9:20     15 min    10 mph +    150 Ft      64.2             5 Ft            Level       Mixed         N/A                      Windy
31    Tower Road/49th Avenue             6/9/2004      Type 2     9:05-9:20     15 min    10 mph +     50 Ft      66.1             5 Ft            Level       Mixed         N/A                      Windy
                                                                                                                               5 Ft-next to
32    Piccadilly Road/48th Avenue        6/29/2004     Type 1    10:30-10:45    15 min     5 mph        71 Ft     55.6          backyards           -3       Residential     N/A
33    Oneida Street/E. 52nd Place        9/12/06       Type 1    11:15-11:30    15 min    3-5 mph      125 Ft     69.2             5 Ft             +6       Residential     N/A     72.2-69.2=3.0
                                                                                                                                                                                                      Ambient reading in
34    High Street/47th Avenue            9/12/06       Type 1     3:15-3:30     15 min    3-5 mph      800 Ft     54.2            5 Ft             Level     Residential     N/A                      neighborhood
                                                                                                                                                                                                      Ambient reading in
35     High Street/48th Avenue               9/12/06  Type 1       2:15-2:30     15 min   3-5 mph     1000 Ft     53.9            5 Ft             Level     Residential     N/A                      neighborhood
36     Vine Street/47th Avenue               9/12/06  Type 1       2:45-3:00     15 min   3-5 mph     500 Ft      61.3            5 Ft              +20      Residential     N/A                      Purina conveyor
37     I-70 /Quebec St (Best Western)        5/11/07  Type 1     12:27-12:42     15 min   3-5 mph     240 Ft      62.3            5 Ft             Level       Hotel         N/A                      Ambient reading
37     I-70 /Quebec St (Best Western)        5/11/07  Type 1      12:46-1:01     15 min   3-5 mph     240 Ft      62.1            5 Ft             Level       Hotel         N/A                      Ambient reading
       I-70 /Quebec St (Sand Creek
38     Greenway)                             5/11/07  Type 2     12:26-12:41     15 min   3-5 mph      90 Ft      62.3            5 Ft             Level        Trail        N/A                      Ambient reading
       I-70 /Quebec St (Sand Creek
38     Greenway)                             5/11/07  Type 2     12:44-12:59     15 min   3-5 mph      90 Ft      61.9            5 Ft             Level        Trail        N/A                      Ambient reading
       I-70 /Quebec St (Northfield Pond
39     Park)                                 5/11/07  Type 2     11:33-11:48     15 min   3-5 mph      900 Ft     62.7            5 Ft             Level     Trail/Park      N/A                      Ambient reading
       I-70 /Quebec St (Northfield Pond
39     Park)                                 5/11/07  Type 2     11:50-12:05     15 min   3-5 mph      900 Ft     63.1            5 Ft             Level     Trail/Park      N/A                      Ambient reading
*All noise readings were taken Between 8AM and 5PM except two 24-hr noise readings
** Meters were placed 5 Ft above existing surface
***Roadway elevation in relation to monitoring point




 A4                                                                                                                                                                                                                 November 2008
I-70 East Draft Environmental Impact Statement                               Traffic Noise Technical Report


                        Time History Graphs for 24-hour Noise Readings

                                Site 1 – Blazer (Sable Boulevard and Smith Road)

                                                  Blazer
                                          24-hour noise readings
                       100
                        90
                        80
                        70
                        60                                                            Leq
                dBa




                        50
                                                                                      Ldn
                        40
                                                                                      L(33)
                        30
                        20
                        10
                            0
                        :1 0
                        :0 0
                        :4 0
                        :3 0
                        :1 0
                        :0 0
                        :4 0
                       1: :00
                        :3 0




                       3: :00
                       5: :00
                       6: :00
                       8: :00
                               0
                      13 0:0
                      15 5:0
                      16 0:0
                      18 5:0
                      20 0:0
                      22 5:0
                      23 0:0
                      11 0:0




                            :0
                           5
                         30
                         15
                         00
                         45
                         30
                         5
                       9:




                                                Time (Hours/Min)


                        Site 2 – Western Belting (Steele Street and 42nd Avenue)

                                              Western Belting
                                          24-hour noise readings

                      120

                      100

                       80
                                                                                       Leq
               dBa




                       60                                                              Ldn
                                                                                       L(33)
                       40

                       20

                        0
                     10 :00
                     11 :00
                     12 :00
                     13 :00
                     13 :00
                     14 :00
                     15 :00
                     16 :00
                     16 :00
                     17 :00
                             00
                      9: 00
                     10 :00




                          0:
                            :


                          0
                          5
                          0
                          5
                          0
                          5
                          0
                          5
                          0
                          5
                        35
                        25
                       :0
                       :4
                       :3
                       :1
                       :0
                       :4
                       :3
                       :1
                       :0
                       :4
                       :3
                      8:




                                                Time (Hours/Min)




November 2008                                                                                           A5
Traffic Noise Technical Report                                 I-70 East Draft Environmental Impact Statement


                           Site 3 – Whittier Lofts (Downing Street and 29th Avenue)

                                                Whittier Lofts
                                            24-hour noise readings

                       100
                        90
                        80
                        70
                        60                                                              Leq
                dBa




                        50                                                              Ldn
                        40                                                              L(33)
                        30
                        20
                        10
                         0
                         :1 0
                         :0 0
                         :4 0
                         :3 0
                         :1 0
                        1: :00




                         :1 0
                              00
                        2: :00
                        4: :00
                        6: :00
                        8: :00
                        9: :00

                         :3 0
                       16 0:0
                       18 5:0
                       19 0:0
                       21 5:0
                       23 0:0




                       13 0:0
                       11 5:0


                            5:
                            5
                          00
                          45
                          30
                          15
                          00
                         :3




                          4
                      14




                                                  Time (Hours/Min)




                                Site 4 – Coors Field (Blake Street and 33rd Avenue)

                                                 Coors Field
                                            24-hour noise readings
                           90
                           80
                           70
                           60
                                                                                         Leq
                           50
               dBa




                           40                                                            Ldn
                           30                                                            L(33)
                           20
                           10
                            0
                       1: :00
                       3: :00
                       5: :00
                       7: :00
                       8: :00

                         :3 0
                         :0 0
                         :4 0
                         :3 0
                         :1 0
                       0: :00




                         :1 0
                         :0 0
                              00
                      10 5:0
                      17 5:0
                      18 0:0
                      20 5:0
                      22 0:0




                      12 0:0
                      14 5:0
                            0:
                            5
                          00
                          45
                          30
                          15
                          00
                          4
                         :1
                      15




                                                  Time (Hours/Min)




A6                                                                                           November 2008
I-70 East Draft Environmental Impact Statement                           Traffic Noise Technical Report


                 Site 5 – Park Hill Golf Course (Colorado Boulevard and Smith Road)

                                              Park Hill
                                       24-hour noise readings
                        100
                            90
                            80
                            70
                            60
                                                                                    Leq
                dBa




                            50
                                                                                    Ldn
                            40
                            30                                                      L(33)
                            20
                            10
                             0
                          :0 0
                          :4 0
                          :3 0
                          :1 0
                          :0 0
                          :4 0
                          :3 0
                         0: :00
                         2: :00
                         3: :00
                         5: :00
                         7: :00
                         9: :00
                                 0
                        12 0:0
                        13 0:0
                        15 5:0
                        17 0:0
                        19 5:0
                        20 0:0
                        22 5:0




                              :0
                             0
                           15
                           00
                           45
                           30
                           15
                           00
                          :2
                       10




                                             Time (Hours/Min)




                        Site 6 – Red Ball Moving (42nd Avenue and Madison Street)

                                          Red Ball Moving
                                       24-hour noise readings
                            100
                             90
                             80
                             70
                             60
                                                                                    Leq
                 dBa




                             50
                                                                                    Ldn
                             40
                             30                                                     L(33)
                             20
                             10
                               0
                              :1 0
                              :0 0
                              :4 0
                              :3 0
                              :1 0
                              :0 0
                              :4 0
                             1: :00




                                   00
                             3: :00
                             5: :00
                             6: :00
                             8: :00

                              :1 0
                            13 :0
                            15 5:0
                            16 0:0
                            18 5:0
                            20 0:0
                            22 5:0
                            23 0:0




                            10 0:0
                                 5:
                           0




                                 5
                               30
                               15
                               00
                               45
                        :4




                               3
                       11




                                             Time (Hours/Min)




November 2008                                                                                       A7
APPENDIX B
            I-70 East Draft Environmental Impact Statement                                                                   Traffic Noise Technical Report


COLORADO DEPARTMENT OF TRANSPORTATION
NOISE ABATEMENT DETERMINATION

Instructions:        To complete this form refer to CDOT Noise Analysis Guidelines

Project #                                            Project Code (SA#)                      STIP#                                    Project Location I-70 East
AQR R600-165                                                                                                                          Section 1 Globeville
A. FEASIBILITY
1.   Can a continuous noise barrier or berm be constructed?.........................                      YES         NO
2.   Can a substantial noise reduction be achieved by constructing a noise barrier or berm?
     10 dBA:          YES         NO           7-10 dBA          Yes        No         5-7 dBA            YES         NO
3.   Are there any “fatal flaw” safety or maintenance issues involving the proposed barrier or berm?                                      Yes       No
B.   REASONABLENESS:                                            EXTREMELY                         REASONABLE                    MARGINALLY                UNREASONABLE
                                                                REASONABLE                                                     REASONALBE
1.   Cost Benefit Index (per receiver per dBA)…                      Less than $3000                   $3000-$3750                  $3750-$4000            More than $4000
2.   Average Build Noise Level…………………...                              70 dBA or More                   66-70 dBA                    63-66 dBA             Less than 63 dBA
3.   Impacted persons’ desires……………………                                More than 75%                    50%-75%                      25%-50%                Less than 25%
4.   Development Type (Category B)…………….                              More than 75%                    50%-75%                      25%-50%               Less than 25%
5.   Development Existence (15 years or more).                       More than 75%                     50%-75%                      25%-50%                Less than 25%
6.   Build Noise Level vs. Existing Noise Level…                     Greater than 10 dBA                5-10 dBA                    0-5 dBA                Noise Level
              Decrease
C.   INSULATION CONSIDERATION:
1.   Are normal noise abatement measures physically infeasible or economically unreasonable?.....................                                   YES         NO
     If the answer to 1 is YES, then:
2.   a. Does this project have noise impacts to public or non-profit buildings? .................................................                   YES        NO
     b. If yes, is it reasonable and feasible to provide insulation for these buildings? .......................................                    YES        NO
3.   a. Is private residential property affected by a 30 dB(A) or more noise level increase? .............................                          YES         NO
     b. Are private residences impacted by 75 dB(A) or more? .........................................................................              YES         NO
D.   ADDITIONAL CONSIDERATIONS:
Globeville has existing 10-foot high noise barriers along I-70. Retrofitting the existing barriers to accommodate a possible 20-foot barrier
would be a considerable challenge structurally and cost prohibitive. Reconstruction of the existing noise barriers would most likely be
required.
E.    DECISION:
1.   Are noise mitigation measures feasible? ....................................................................................................   YES        NO
2.   Are noise mitigation measures reasonable? ...............................................................................................      YES        NO
3.   Is insulation of buildings both feasible and reasonable? .............................................................................         YES        NO
4.   Shall noise mitigation measures be provided? ............................................................................................      YES        NO
F.   DECISION DESCRIPTION AND JUSTIFICATION
The average residences in the Globeville neighborhood currently experience average noise levels between just below 66 dBA due to an
existing 10 foot noise barrier. The 2030 alternative noise level for front-row receivers will increase by less than 1 dBA to just over 66 dBA.
Additional 10 feet of height on the existing noise barrier, total of a 20-foot reconstructed barrier, can provide a minimum of 5 dBA noise
reductions to 14 front-row homes and 3 dBA to 37 more homes. The cost benefit index for this alternative is roughly $16,900 per benefited
receiver. Based on the inaudible increase of less than 1 dBA , the minimal noise levels and cost benefit index noise mitigation does not
appear to be reasonable.

Completed by: PBSJ                                                                              Date: 10/24/06


                                                                                                                                  CDOT Form #1209            12/02




            November 2008                                                                                                                                        B1
             Traffic Noise Technical Report                                                        I-70 East Draft Environmental Impact Statement


COLORADO DEPARTMENT OF TRANSPORTATION
NOISE ABATEMENT DETERMINATION

Instructions:         To complete this form refer to CDOT Noise Analysis Guidelines

Project #                                            Project Code (SA#)                       STIP#                                   Project Location I-70 East
AQR R600-165                                                                                                                          Section 2 Elyria-Swansea
G. FEASIBILITY
4.    Can a continuous noise barrier or berm be constructed?.........................                     YES         NO
5.    Can a substantial noise reduction be achieved by constructing a noise barrier or berm?
      10 dBA:         YES          NO           7-10 dBA         Yes         No        5-7 dBA            YES         NO
6.    Are there any “fatal flaw” safety or maintenance issues involving the proposed barrier or berm?                                      Yes        No
H.    REASONABLENESS:                                            EXTREMELY                         REASONABLE                   MARGINALLY                 UNREASONABLE
                                                                 REASONABLE                                                    REASONALBE
7.    Cost Benefit Index (per receiver per dBA)…                      Less than $3000                   $3000-$3750                  $3750-$4000            More than $4000
8.    Average Build Noise Level…………………...                             70 dBA or More                   66-70 dBA                    63-66 dBA               Less than 63 dBA
9.    Impacted persons’ desires……………………                               More than 75%                     50%-75%                     25%-50%                 Less than 25%
10.   Development Type (Category B)…………….                             More than 75%                     50%-75%                     25%-50%                 Less than 25%
11.   Development Existence (15 years or more).                       More than 75%                    50%-75%                      25%-50%                 Less than 25%
12.   Build Noise Level vs. Existing Noise Level…                     Greater than 10 dBA               5-10 dBA                    0-5 dBA                 Noise Level
               Decrease
I.    INSULATION CONSIDERATION:
4.    Are normal noise abatement measures physically infeasible or economically unreasonable?.....................                                    YES        NO
      If the answer to 1 is YES, then:
5.    a. Does this project have noise impacts to public or non-profit buildings? .................................................                    YES        NO
      b. If yes, is it reasonable and feasible to provide insulation for these buildings? .......................................                     YES        NO
6.    a. Is private residential property affected by a 30 dB(A) or more noise level increase? .............................                           YES        NO
      b. Are private residences impacted by 75 dB(A) or more? .........................................................................               YES        NO
J.    ADDITIONAL CONSIDERATIONS:




K.    DECISION:
5.    Are noise mitigation measures feasible? ....................................................................................................    YES        NO
6.    Are noise mitigation measures reasonable? ...............................................................................................       YES        NO
7.    Is insulation of buildings both feasible and reasonable? .............................................................................          YES        NO
8.    Shall noise mitigation measures be provided? ............................................................................................       YES        NO
L.    DECISION DESCRIPTION AND JUSTIFICATION
The average residences in the Elyria and Swansea neighborhoods currently experience average noise levels between 65 and 70 dBA. The
2030 no-action and build noise level will remain in the same general levels. However, the various potential shifts in the roadway will move
the impacts. Noise barriers can provide a minimum of 5 dBA noise reductions to several rows of homes for all alternatives and 3 dBA to still
many more homes. The cost benefit index for all alternatives range from $3500 to $6000 per benefited receiver. Based on all the above
noted issues noise mitigation appears to be feasible and reasonable. Additional analysis will be conducted and a final abatement
determination will be made in the FEIS.
Completed by: PBSJ                                                                              Date: 10/24/06


                                                                                                                                  CDOT Form #1209             12/02




             B2                                                                                                                                      November 2008
             I-70 East Draft Environmental Impact Statement                                                                   Traffic Noise Technical Report


COLORADO DEPARTMENT OF TRANSPORTATION
NOISE ABATEMENT DETERMINATION

Instructions:         To complete this form refer to CDOT Noise Analysis Guidelines

Project #                                            Project Code (SA#)                       STIP#                                   Project Location I-70 East
AQR R600-165                                                                                                                          Section 3 – Commerce City
M. FEASIBILITY
7.    Can a continuous noise barrier or berm be constructed?.........................                     YES         NO
8.    Can a substantial noise reduction be achieved by constructing a noise barrier or berm?
      10 dBA:         YES          NO           7-10 dBA         Yes         No        5-7 dBA            YES         NO
9.    Are there any “fatal flaw” safety or maintenance issues involving the proposed barrier or berm?                                      Yes       No
N.    REASONABLENESS:                                            EXTREMELY                         REASONABLE                   MARGINALLY                UNREASONABLE
                                                                 REASONABLE                                                    REASONALBE
13.   Cost Benefit Index (per receiver per dBA)…                      Less than $3000                   $3000-$3750                  $3750-$4000           More than $4000
14.   Average Build Noise Level…………………...                             70 dBA or More                   66-70 dBA                    63-66 dBA              Less than 63 dBA
15.   Impacted persons’ desires……………………                               More than 75%                     50%-75%                     25%-50%                Less than 25%
16.   Development Type (Category B)…………….                             More than 75%                     50%-75%                     25%-50%                Less than 25%
17.   Development Existence (15 years or more).                       More than 75%                    50%-75%                      25%-50%                Less than 25%
18.   Build Noise Level vs. Existing Noise Level…                     Greater than 10 dBA               5-10 dBA                    0-5 dBA                Noise Level
               Decrease
O.    INSULATION CONSIDERATION:
7.    Are normal noise abatement measures physically infeasible or economically unreasonable?.....................                                   YES        NO
      If the answer to 1 is YES, then:
8.    a. Does this project have noise impacts to public or non-profit buildings? .................................................                   YES        NO
      b. If yes, is it reasonable and feasible to provide insulation for these buildings? .......................................                    YES        NO
9.    a. Is private residential property affected by a 30 dB(A) or more noise level increase? .............................                          YES        NO
      b. Are private residences impacted by 75 dB(A) or more? .........................................................................              YES        NO
P.    ADDITIONAL CONSIDERATIONS:




Q.    DECISION:
9.    Are noise mitigation measures feasible? ....................................................................................................   YES        NO
10.   Are noise mitigation measures reasonable? ...............................................................................................      YES        NO
11.   Is insulation of buildings both feasible and reasonable? .............................................................................         YES        NO
12.   Shall noise mitigation measures be provided? ............................................................................................      YES        NO
R.    DECISION DESCRIPTION AND JUSTIFICATION
The average residences in the Commerce City neighborhood currently experience average noise levels between 65 and 70 dBA. While the
2030 alternatives noise level average above 70 dBA. Noise barriers can provide a minimum of 5 dBA noise reductions to several rows of
homes for all alternatives and 3 dBA to still more homes. The cost benefit index for all alternatives range from $4700 to $5500 per benefited
receiver. Based on all the above noted issues noise mitigation appears to be reasonable and feasible. Additional analysis will be conducted
and a final abatement determination will be made in the FEIS.

Completed by: PBSJ                                                                              Date: 10/24/06


                                                                                                                                  CDOT Form #1209            12/02




             November 2008                                                                                                                                       B3
             Traffic Noise Technical Report                                                        I-70 East Draft Environmental Impact Statement


COLORADO DEPARTMENT OF TRANSPORTATION
NOISE ABATEMENT DETERMINATION

Instructions:         To complete this form refer to CDOT Noise Analysis Guidelines

Project #                                            Project Code (SA#)                       STIP#                                   Project Location I-70 East
AQR R600-165                                                                                                                          Section 4&5 Montbello
S.   FEASIBILITY
10.   Can a continuous noise barrier or berm be constructed?.........................                     YES         NO
11.   Can a substantial noise reduction be achieved by constructing a noise barrier or berm?
      10 dBA:         YES          NO           7-10 dBA         Yes         No        5-7 dBA            YES         NO
12.   Are there any “fatal flaw” safety or maintenance issues involving the proposed barrier or berm?                                      Yes        No
T.    REASONABLENESS:                                            EXTREMELY                         REASONABLE                   MARGINALLY                 UNREASONABLE
                                                                 REASONABLE                                                    REASONALBE
19.   Cost Benefit Index (per receiver per dBA)…                      Less than $3000                   $3000-$3750                  $3750-$4000            More than $4000
20.   Average Build Noise Level…………………...                             70 dBA or More                   66-70 dBA                    63-66 dBA               Less than 63 dBA
21.   Impacted persons’ desires……………………                               More than 75%                     50%-75%                     25%-50%                 Less than 25%
22.   Development Type (Category B)…………….                             More than 75%                     50%-75%                     25%-50%                 Less than 25%
23.   Development Existence (15 years or more).                       More than 75%                    50%-75%                      25%-50%                 Less than 25%
24.   Build Noise Level vs. Existing Noise Level…                     Greater than 10 dBA               5-10 dBA                    0-5 dBA                 Noise Level
               Decrease
U.    INSULATION CONSIDERATION:
10.   Are normal noise abatement measures physically infeasible or economically unreasonable?.....................                                    YES        NO
      If the answer to 1 is YES, then:
11.   a. Does this project have noise impacts to public or non-profit buildings? .................................................                    YES        NO
      b. If yes, is it reasonable and feasible to provide insulation for these buildings? .......................................                     YES        NO
12.   a. Is private residential property affected by a 30 dB(A) or more noise level increase? .............................                           YES        NO
      b. Are private residences impacted by 75 dB(A) or more? .........................................................................               YES        NO
V.    ADDITIONAL CONSIDERATIONS:




W.    DECISION:
13.   Are noise mitigation measures feasible? ....................................................................................................    YES        NO
14.   Are noise mitigation measures reasonable? ...............................................................................................       YES        NO
15.   Is insulation of buildings both feasible and reasonable? .............................................................................          YES        NO
16.   Shall noise mitigation measures be provided? ............................................................................................       YES        NO
X.    DECISION DESCRIPTION AND JUSTIFICATION
The average residences in the front-row receivers in the Montbello neighborhood currently experience noise levels of approximately 65 dBA
with the existing 10-foot barrier along I-70. The 2030 alternative noise levels will increase approximately 1.5 dBA over today’s levels with
the existing barrier in place. Based on the analysis, a range of barrier heights from 12 to 20 feet would not provide the minimum five dBA
reduction to first-row receivers. At this time, mitigations does not appear to be feasible and reasonable. However, additional analysis will be
conducted and a final abatement determination will be made in the FEIS.

Completed by: PBSJ                                                                              Date: 10/24/06


                                                                                                                                  CDOT Form #1209             12/02




             B4                                                                                                                                      November 2008
             I-70 East Draft Environmental Impact Statement                                                                   Traffic Noise Technical Report


COLORADO DEPARTMENT OF TRANSPORTATION
NOISE ABATEMENT DETERMINATION

Instructions:         To complete this form refer to CDOT Noise Analysis Guidelines

Project #                                            Project Code (SA#)                       STIP#                                   Project Location I-70 East
AQR R600-165                                                                                                                          Section 5 – S of I-70 and E of I-225
Y.   FEASIBILITY
13.   Can a continuous noise barrier or berm be constructed?.........................                     YES         NO
14.   Can a substantial noise reduction be achieved by constructing a noise barrier or berm?
      10 dBA:         YES          NO           7-10 dBA         Yes         No        5-7 dBA            YES         NO
15.   Are there any “fatal flaw” safety or maintenance issues involving the proposed barrier or berm?                                      Yes       No
Z.    REASONABLENESS:                                            EXTREMELY                         REASONABLE                   MARGINALLY                UNREASONABLE
                                                                 REASONABLE                                                    REASONALBE
25.   Cost Benefit Index (per receiver per dBA)…                      Less than $3000                   $3000-$3750                  $3750-$4000           More than $4000
26.   Average Build Noise Level…………………...                             70 dBA or More                   66-70 dBA                    63-66 dBA              Less than 63 dBA
27.   Impacted persons’ desires……………………                               More than 75%                     50%-75%                     25%-50%                Less than 25%
28.   Development Type (Category B)…………….                             More than 75%                     50%-75%                     25%-50%                Less than 25%
29.   Development Existence (15 years or more).                       More than 75%                    50%-75%                      25%-50%                Less than 25%
30.   Build Noise Level vs. Existing Noise Level…                     Greater than 10 dBA               5-10 dBA                    0-5 dBA                Noise Level
               Decrease
AA. INSULATION CONSIDERATION:
13.   Are normal noise abatement measures physically infeasible or economically unreasonable?.....................                                   YES        NO
      If the answer to 1 is YES, then:
14.   a. Does this project have noise impacts to public or non-profit buildings? .................................................                   YES        NO
      b. If yes, is it reasonable and feasible to provide insulation for these buildings? .......................................                    YES        NO
15.   a. Is private residential property affected by a 30 dB(A) or more noise level increase? .............................                          YES        NO
      b. Are private residences impacted by 75 dB(A) or more? .........................................................................              YES        NO
BB. ADDITIONAL CONSIDERATIONS:




CC. DECISION:
17.   Are noise mitigation measures feasible? ....................................................................................................   YES        NO
18.   Are noise mitigation measures reasonable? ...............................................................................................      YES        NO
19.   Is insulation of buildings both feasible and reasonable? .............................................................................         YES        NO
20.   Shall noise mitigation measures be provided? ............................................................................................      YES        NO
DD. DECISION DESCRIPTION AND JUSTIFICATION
These large lot residences currently experience average noise levels of 66.4 dBA with one receiver experiencing 70 dBA. The 2030 build
noise level will increase an inaudible 1.7 dBA on average to an overall average of 68.1. A noise barrier providing a minimum of 5 dBA
noise reduction for these 8 residences would be required to be 1900 feet long and 16 feet high. The cost benefit index equals (1900 feet
long x 16 feet high x $30 per square foot) divided by (8 receivers x 5 dB reduction) = $22,800 per receiver per dB. Based on all the above
noted issues noise mitigation appears to not be reasonable and feasible. However, additional analysis will be conducted and a final
abatement determination will be made in the FEIS.
Completed by: PBSJ                                                                              Date: 10/24/06


                                                                                                                                  CDOT Form #1209            12/02




             November 2008                                                                                                                                       B5
Traffic Noise Technical Report                        I-70 East Draft Environmental Impact Statement




                                 This page intentionally left blank.




B6                                                                                  November 2008