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					           Highway Traffic and
             Safety Analyses


              Lecture 7:
            Parking Studies


    Purdue University
School of Civil Engineering
     West Lafayette
       Lecture Outline

•   Definitions
•   Demand vs. Supply
•   Parking Inventory
•   Accumulation Studies
•   License Plate Checks
                 Definitions
• Parking volume (veh/day)
  – Number of vehicles parking in a study area
    during a specific length of time (typically a day).
    Vehicles leaving the parking area and returning
    are counted twice.
• Parking accumulation (veh)
  – Number of vehicles parking at a specific time
• Parking accumulation curve
  – A curve showing variation of parking
    accumulation over time
               Definitions
• Parking load (veh-hour)
  – The area under the parking accumulation curve
• Parking duration (hour)
  – Average parking time
• Parking turnover (veh/space)
  – Number of vehicles per parking space during
    the analyzed period
                             Accumulation Curve
Accumulation (veh)




                                                               Time (hrs)

                     6   9    12   15   18   21   24   3   6
                              Demand vs. Supply
                                       Maximum
                                       Demand
                                                              No. of Legal
Accumulation (veh)




                                                                 Spots




                             True Demand
                                                                     Time (hrs)

                     6   9      12   15    18   21   24   3      6
                              Demand vs. Supply

                                                Hidden Demand
Accumulation (veh)




                             Illegal Parking
                                                                        Time (hrs)

                     6   9       12    15      18   21   24     3   6
            Parking Inventory
• Number of parking spaces
• Time limits and hours of operation
• Type of ownership
• Rates and method of fee collection
• Parking regulations at curb spaces (loading zones,
  passenger zones, handicapped zones, taxi zones,
  bus zones)
• Lot or garage
• Degree of permanency
        Parking Inventory
            Numbering System
                            Curb Face
                             Number

    1                   1            Block        1
                5                   Number

                                      2   4
5       2   4       6       6                     7
                                            Off-
                                7          Street
    3                   3                 Facility 3
                                          Number
                              Curb Face
                               Number


    1                     1            Block          1

                                                             Parking Inventory
                  5                   Number


                                        2 4
5           2 4       6       6                       7              Summary Sheet
                                             Off-
                                  7         Street
    3                     3                Facility   3
                                           Number

                                                            Inventory Data
Block        Facility Parking                  Non-public   Data 3   Data 4   Data 5   …..
                              Spaces           Spaces
        5         1                    7              0
        5         2                   12              0
        5         3                    7              0
        6         1                   12              4
        Area and Time of Parking
         Accumulation Studies
• Study area – parking area for the studied
  development
• On days when maximum parking is expected
• Counting period should include time of intense
  parking
   – 6 AM to 8 PM for employment and commercial sites
     (several times)
   – 1 AM to 5 AM should be covered in residential areas
     (once)
     Techniques of Parking Demand
                Studies

•   Cordon-based without vehicles identification
•   Cordon-based with vehicles identification
•   Route-based without vehicles identification
•   Route-based with vehicles identification
     Cordon-Based Parking Study
     without Vehicles Identification

• Estimating the initial accumulation by
  counting along routes
• Continuous counting of vehicles entering and
  exiting the study area
• Estimating the final accumulation by counting
  along routes
   Cordon-Based Parking Study with
        Vehicles Identification

• Estimating the initial accumulation by
  counting along routes
• Manual recording of license numbers when
  low flows
• Videotaping of license numbers with post-
  processing when large flows
• Estimating the final accumulation by counting
  along routes
   Route-Based Accumulation Studies
     without Vehicles Identification
– Counting along a pre-specified route that covers the
  study area
– Careful routes design for large areas (multiple field
  checkers)
– Counting vehicles or empty spaces (what easier)
– Counting interval: one or two hours
– 5-hour shifts
– Common starting point helps supervising
 Route-Based Accumulation Studies
    with Vehicles Identification
• Hand-held computers, tape recorders, or paper
  worksheets
• Counting interval: 1/3 of the average parking
  duration and not longer than 1-2 hours
• 1 ½ minutes per one parking space needed
• 5-hour shifts
• Careful routes design for large areas (multiple
  field checkers)
• Common starting point helps supervising
                Exercise 1




Parking vehicles were counted every two hours
Draw a parking accumulation curve, calculate the
parking load based on the parking counts.
        License Plate Checks
                 Calculations

  Turnover = Parking Volume/Parking Spaces

               Parking Load =
Av. Accumulation x No. of Intervals x Av. Interval



          Average Parking Duration =
         Parking Load/Parking Volume
                 Exercise 2




The license plates were noted every two hours.
Determine the parking volume and calculate the
parking turnover and the average parking duration.
       Results Obtainable from Various
          Parking Study Techniques
Results           Cordon           Cordon with      Routes           Routes with
                  without          Identification   without          Identification
                  Identification                    Identification
Accumulation           Yes              Yes              Yes              Yes
Volume                 Yes              Yes               No              Yes
Turnover               Yes              Yes               No              Yes
Average                Yes              Yes               No              Yes
Duration
Variability of          No              Yes               No              Yes
Duration
Space use               No               No              Yes              Yes
Illegal parking      Yes/No           Yes/No             Yes              Yes
Enforcement             No               No               No              Yes

				
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posted:10/8/2013
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