Department of Planning
County Building Three 6582 Main Street
PHONE (804) 693-1224 P. O. Box 329
FAX (804) 693-4664 Gloucester, Virginia 23061
M E M O R A N D U M
TO: Bill Whitley, County Administrator
FROM: Jay Scudder, Director of Planning
DATE: December 19, 2006
SUBJECT: Roundabout Feasibility
Attached for your information is the Roundabout Feasibility Study initiated by the
Planning Department in order to determine whether a modern roundabout could
improve the safety, traffic flow, capacity and aesthetics at the intersection of 3, 14
and business 17.
This intersection has been a concern for a long time. The 1991 Comprehensive
Plan mentions preplanning this major intersection to create a catalyst for Village
Center Form. The study was initiated as the result of several factors, the
anticipated completion of the Main Street Enhancement Project, the Economic
Development Authority and Gloucester Main Street Association’s redevelopment
interests in the “village”. However, the primarily emphasis was based on
continued traffic control problems at this intersection.
The County has requested that VDOT conduct a study to investigate the
realignment and/or other potential improvements to move traffic more efficiently
and safely at this intersection at the Annual Primary Road Hearings over the past
several years. The Virginia Department of Transportation has responded to these
requests with the recent signalization changes that cost $150,000. The modern
roundabout at Fox Mill Center, with substantial reengineering cost $250,000.
A modern roundabout at this key intersection provides a proactive traffic control
option for meeting the community’s future development goals. Based on input
from several professional transportation engineers and planners, this location is
an ideal candidate for a modern roundabout. Modern roundabouts throughout the
country incorporate architectural design and landscaping to create attractive
gateways into communities. A modern roundabout at this intersection could
provide a catalyst towards redevelopment efforts for the south end of Main
Street. The design would provide a pedestrian friendly feature consistent with the
existing and historic Village development form that is envisioned by the
According to the analysis, today this intersection functions at a level of service F
at peak AM and PM times of the day. A level of service F represents a failing
level of service. Without improvements this intersection will have difficulty
accommodating future growth. Since this intersections is a regional traffic point
the impacts from continued growth pose significant concern. Additionally, the
ability to bypass or redirect traffic at this location would involve significant cost,
right of way acquisition, time and geographic hurdles. Based on the results of the
analysis, traffic safety, capacity and efficiency will function at high level of service
well into the future with a modern roundabout. The analysis indicates that a
multiple lane modern roundabout will provide A & B levels of service well into the
future. In order to improve this intersection with signalization improvements for
increased capacity only a C level of service seems feasible. The signalized
improvements involve significant right of way and impacts to adjoining
businesses because it would impact all three legs of the intersection. From a
comparison perspective the intersection at Guinea Road and 17 currently
functions at a D level of service at peak hours. The D level of service represents
a “functioning” or acceptable level of service for an urban traffic standard,
although additional traffic may result in it becoming an F.
The purpose of this study is to present an option to the Board of Supervisors on
an alternative to the existing signalized intersection at routes 3, 14 and Business
17. If the Board of Supervisors chooses to adopt the “Roundabout Feasibility
Study” as a viable improvement option for this intersection staff will proceed with
the development of a roundabout at this location. The adoption of this study
would be very similar to the recent “Crossover Study” for the Route 17 Corridor.
The 17 Crossover Study once adopted by the Board of Supervisors was
designed and funded by VDOT. The unique transportation capacity and
enhancement qualities of a roundabout design could provide for additional
transportation funding sources not available in standard road improvement
projects, namely air quality sources.
The Roundabout Feasibility Study represents a proactive approach for
community development oriented planning to improve the transportation system
and enhance the quality of life in the community. Throughout the Country, State
transportation organizations including VDOT have adopted legislation that
encourages modern roundabouts to be considered as alternatives for signalized
intersections. Both the Federal Highway Administration and The Insurance
Institute for Highway Safety support roundabouts because of increased safety.
Modern Roundabouts have been demonstrated to more efficiently accommodate
traffic, reduce conflict points and greatly improve safety than other forms of at
grade intersections. Additionally, roundabouts have been successfully utilized to
enhance and create attractive gateways to communities. Planning Staff
recommends that the Board of Supervisors adopt the “Roundabout Feasibility
Study” and proceed with investigating the implementation process.
After reviewing the merits and results of the study for consideration, the Planning
Commission voted in December to forward this study to the Board of Supervisors
for Information purposes.
The proposed Modern Roundabout represents a component of a long-range plan
for the continued enhancement of the Village and the County’s overall
transportation network. In 2006 Gloucester County became eligible for
Congestion Management and Air Quality (CMAQ) improvement program funds.
These federally allocated funds are available for transportation projects that
improve congestion and reduce emissions. A modern roundabout could score
high on the project list through the Hampton Roads Metropolitan Organization for
special CMAQ funds. Adoption of this plan would enable the County to seek
additional funding sources such as this to make the plan a reality.
! #$ &
%( + % ,-
' )* (+
! #. &
) . /0
MODERN ROUNDABOUT FEASIBILITY STUDY FOR THE INTERSECTION OF
MAIN STREET AND JOHN CLAYTON MEMORIAL HIGHWAY (ROUTES 3/14)
This report provides the findings of an assessment of the Preliminary Feasibility of a
modern roundabout at the Gloucester, Virginia intersection of Main Street and John Clayton
Memorial Highway (Routes 3/14). This “T” intersection is one (1) of two (2) gateways to the
“downtown” Gloucester Main Street area and its historic courtyard district. The study effort
included development of some conceptual roundabout concepts, and associated traffic analysis of
the potential benefits of such an intersection control.
Figure 1 shows the location of this critical intersection to the immediate surrounding
area. As previously stated, this intersection is the western gateway to the part of the historic
downtown area. This area served by Main Street, which is a 2-lane roadway with parking on
both sides. Of importance at this intersection is the fact that the Route 3 leg and the eastern
(business Route 17) leg essentially form a 90-degree through movement of area, or regional,
traffic essentially bypassing the downtown area accessible by Main Street on the west leg. The
current unacceptable traffic conditions, and the overall dilapidated appearance of this area, have
contributed to the desire to improve both traffic conditions and aesthetics of this Gloucester
The Modern Roundabout
Modern roundabouts have been in the United States for over 20 years, and are relatively
common in many other states, with Virginia trailing behind most other states in taking advantage
of these very effective forms of intersection traffic control. Roundabouts are characterized by
“splitter” approaches, which provide a controlled curve into the intersection, Yield signs on these
approaches, inner circles that are engineered for speeds in the 15-20 mile per hour (mph) range,
and when properly designed, incorporate extensive landscaping that both provides aesthetics as
well as reinforcing safe traffic control. Modern roundabouts are fundamentally different from
older rotaries, trumpet intersections, and traffic circles, which often are characterized by tight
weaving designs, high speed, large, inner circles, and traffic signal control. Most residents of the
Gloucester area are no doubt familiar with the multi-lane roundabout installed approximately one
(1) year ago off the intersection of US Route 17/17 Business, and adjacent to Wal-Mart. That
intersection is a 4-lane roundabout, whereas the one for consideration in the downtown area on
Main Street essentially is a 3-leg, “T” intersection roundabout, although there would be a curb-
cut to the commercial parking lot on the south side of the intersection.
The primary benefit of roundabouts are their inherent ability to reduce accidents.
Compared to other intersection controls, especially traffic signals, roundabouts, on average, have
total accident reductions of 50 percent, and reductions of 75 to 90 percent in injury and fatality-
type accidents. The primary reason for this dramatic betterment and safety is the fact that they
are engineered to accommodate all vehicles traveling through the intersection at a safe,
controlled speed of typically 15-20 mph. Under certain traffic conditions, roundabouts also can
much more efficiently accommodate traffic demand.
Figure 2 shows a figure depicting existing roadway geometrics and adjacent land uses.
This intersection is controlled through traffic signals, and essentially has two (2) approaching
lanes on each of the three (3) approaches. The northeast quadrant of the intersection includes an
historic building, the northwest quadrant includes an abandoned old gas station/convenience
store, and the southern side includes a commercial area with parking immediately adjacent to the
Also shown on this figure are existing AM and PM peak hour traffic volumes. As with
most “T” intersections, note that there are significant both left and right turn movements. One
(1) reason a roundabout initially was considered for this location is the fact that, inherently,
roundabouts are much more effective at accommodating intersection turning movements than
Proposed Roundabout Concept
Figure 3 depicts a suggested roundabout concept for the Main Street/Route 3
intersection. The three (3) intersection approaches still maintain, as is the current conditions,
two (2) traffic lane approaches. Sidewalks are provided along each curb edge, as are crosswalks
across each intersection leg provided.
Regarding right-of-way requirements, this concept assumes that no additional right-of-
way is needed on the historic northeast quadrant and the commercial south side of the
intersection. However, additional right-of-way would be required in the northwest quadrant,
which presently includes the abandoned gas station.
Figure 4 provides a graphic presentation of a possible landscaping concept. As
previously stated, the landscaping not only enhances the aesthetics of the intersection, but is a
critical component of reinforcing the horizontal curvature of the intersection and, consequently,
improving intersection safety.
Traffic Level of Service (LOS) Evaluation
A critical component of this study evaluation is the ability of the modern roundabout to
efficiently accommodate traffic. Quality of traffic flow is calculated utilizing traffic models,
which simulate traffic conditions, and are summarized in terms defined as “Levels of Service”
(LOS). LOS range from excellent conditions – “A” LOS – to failing/congested traffic conditions
– “F” LOS. The various LOS are summarized graphically in Table 1.
Table 2 provides a summary of the LOS for the various circumstances evaluated. The
detailed computer simulation worksheets for the results presented for Table 2 are included in the
Appendix of this report.
LEVELS OF SERVICE SUMMARY
LEVEL OF SERVICE
INTERSECTION CONTROL TRAFFIC CONDITIONS AM PM
A. Existing Traffic Signal Control Existing Volumes F F
B. Single Lane Roundabout Existing Volumes B B
C. Multiple Lane Roundabout Existing Volumes A B
D. Multiple Lane Roundabout Existing Plus 33% B B
E. Multiple Lane Roundabout Existing Plus 39% B C
To the surprise of no one who is familiar with this intersection, the AM and PM peak
hour traffic conditions of a typical weekday at this intersection are calculated to be “F”. That is
considerable traffic queuing and an unacceptable amount of delay for the typical driver traveling
through these intersections is experienced.
The first roundabout concept evaluated was a single-lane roundabout, which has the
advantage of conceivably being able to fit within the existing right-of-way. The LOS would
improve dramatically to very acceptable “B” levels for both AM and PM peak hour conditions.
An evaluation of a single-lane roundabout under other traffic conditions indicated some future
constraints. That is, a single-lane roundabout likely would not be able to handle much of an
increase in existing traffic conditions before it would approach unacceptable traffic conditions.
That is, a single-lane roundabout would handle existing volumes very well, but would have little
capacity for future growth.
The multiple lane roundabout, as depicted in Figure 3, experiences excellent “A” (AM
peak hour) and “B” (PM peak hour) LOS based on existing traffic volumes. As indicated in
Table 2, an overall increase of one-third in existing volumes still results in very acceptable “B”
LOS. Finally, an approximate 39 percent in increase in current volumes will result in a very
acceptable “B” in the AM peak and an acceptable “C” LOS in the PM peak. This very likely
represents at least a 10-year growth in traffic if not more.
Figure 4 is a preliminary concept only, and a more detailed analysis could improve upon
its potential design. For example, it would be desirable to have more horizontal deflection in the
Main Street eastbound approach for vehicles entering into the roundabout; likely requiring the
roundabout to shift somewhat farther into the northwest quadrant of the intersection. Also, the
potential for acquiring this parcel obviously needs to be investigated for this concept to proceed
However, based on the analysis presented in this study, it is clear that a multi-lane
roundabout at this location would provide a substantial improvement in traffic flow, improved
safety for vehicles, bicyclists and pedestrians, and provide potential for a significant attractive
gateway into Gloucester. As these benefits are very substantial, it is recommended that the
possibility of a modern roundabout at this location be further pursued.
Signalized Intersection Improvements
The following diagram, Figure 2A, demonstrates the improvements required
to bring the signalized intersection to an improved LOS. For the intersection to produce
acceptable traffic conditions for today, a “C” LOS needs to be acheived. In order to reach
this level of service, additional traffic lanes on all three road sections are required.
The road widening for all three legs of the intersection likely will require an extension of
at least 300 feet on each side of the intersection. The extension of these three legs of the
approach lanes would be required to be up to 14 feet in width (including curb and gutter),
which requires additional right-of-way acquisition.
As demonstrated in Figure 2A, the expansion of a signalized intersection at this
location to accommodate existing and future traffic and an improved LOS
from “F” to “C”, would substantially impact surrounding properties. The impacts
resulting from signalized intersection improvements are more extensive than what is
demonstrated in Figure 4, which incorporates a modern roundabout. Based on Figure 2A,
signalized improvements would impact numerous local businesses and structures due to
the required widening and length of three additional lanes. Additionally, the modern
roundabout minimizes right-of-way impacts and provides a LOS “A” (AM) and "B" (PM)
versus a LOS “C” (AM & PM) for an improved signalized intersection.