09 Parking Studies (Traffic Engineering هندسة المرور & Prof. Saad AlGadhi)

1. CE 436 Traffic Engineering
Topic 9: Parking Studies
Prof. Saad AlGadhi
CE 436 –Traffic Engineering
King Saud University
email: salgadhi@ksu.edu.sa

2. Four Key Parking Issues
1. Parking Generation & Supply Needs
2. Parking Studies & Characteristics
3. Parking Facility Design & Location
4. Parking Programs (not covered)

3. 1. Parking Supply Needs
 How many spaces required? Where?
 Types:
 On-street (curb)
 Off-Street:
 Surface lot
 Garage
 Need for parking depends upon:
 Type and Size of Development Land-Use
 Development general density
 Amount & quality of public transport access available

4. Parking Generation (PG)
 Relates the maximum observed # of occupied
parking spaces to one underlying variable
 ITE’s Parking Generation Manual (4th, 2010)
 Typical Parking Generation:
 Typical PG Specification Units: Table 12.1
 PG Rates: Table 12.2

5. Table 12.1 Typical Parking Generation Specification Units

6. Table 12.2 Typical Parking Generation Rates

7. Table 12.2 (continued) Typical Parking Generation Rates

8. PG Rates Example
 Small office park: 25,000 ft2 Find the
peak parking load expected?
Solution:
 Avg. rate = 2.84 per 1000 ft2
 # parking spaces = 2.84 *25=71 space
 From equation, p= 2.51*25+27=90
 Range [71-90]: Do PG localized study

9. Zoning Regulation
 Specify min. # parking spaces required
for development of specific type & size
 Based upon 85th percentile demand
 Zoning requirements are set 5-10% higher
than the 85th percentile demand
 Recommended values: Table 12.4

10. Table 12.4 Recommended Parking Space Zoning Requirements in Suburban Settings

11. Table 12.4 (continued) Recommended Parking Space Zoning Requirements in Suburban Settings

12. Table 12.4 (continued) Recommended Parking Space Zoning Requirements in Suburban Settings

13. Zoning Regulation
 Handicapped min. spaces: ITE

14. 2. Parking Studies & Charax.
 Critical to supply needs are:
1. Proximity requirements of parkers
2. Accumulation
3. Duration
 Accumulation and Duration Related by
Capacity (space-hours)
 Inventory study is a pre-requisite.

15. Proximity: How Far to Walk
 Varies with:
 trip purpose
 Urban area size (Fig. 12.1)
 Walking distance (Table 12.5)
 85 % park within 0.3 mile (500 m)
 75 % park within 0.25 mile (400 m)
 50 %: 500 ft (150 m)
 Over 1 million population: avg. walking distance is
900 ft (275 m)

16. Figure 12.1 Average Walking Distance by Urbanized Area Population

17. Table 12.5 CBD Walking Distances to Parking Spaced

18. Parking Supply Inventory
 Includes observing:
 # of parking spaces
 Their locations
 Time restrictions on use
 Type of parking facility (on-street, off-
street lot, off-street garage)
 Its data collected manually (on foot),
but ITS recently used.

19. Inventory Methodology
 Study area mapped and precoded (Fig. 12.2)
 Data Field Sheet (Fig. 12.3)
 For unmarked curb parking use:
 7 m (23 ft) for parallel parking
 3.65 m (12 ft) for angle parking
 2.9 m (9.5 ft) for 90-degree parking

20. Figure 12.2 Illustrative System for Parking Location Coding

21. Figure 12.3 A Parking Inventory Field Sheet

22. Inventory Example (p. 258)
 Given:
 11 hr study
 450 spaces available for full 12 hrs.
 280 for 6 hrs
 150 for 7 hrs
 100 for 5 hrs
 Avg. parking duration = 1.4 hr

23. Inventory Example (p. 258)
 Parking supply? Use Equation 12-2.

24. Inventory Example (p. 258)

25. Accumulation & Duration
1. Parking Accumulation: total # of parked
vehicles at any given time.
2. Parking Duration, D: length of time individual
vehicles remain parked.
3. Parking Turnover Rate, TR: # parkers that use
a parking stall over one hour.
4. Occupancy, O = 100 * (max. Accum./Supply)
 Observed by License Plate Survey technique.

26. Figure 12.4 Parking Accumulation in Urbanized Areas by Population

27. Figure 12.5 Parking Duration Versus Urbanized Area Population

28. License Plate Survey
 At regular intervals (10-30 min.)
 observer walks a particular route.
 He records the license plate number of
vehicles occupying each parking space.
 Typical field sheet (Fig. 12.6)

29. Figure 12.6 A License-Plate Parking Survey Sheet

30. Table 12.7 Summary and Computations from a Typical Parking Survey Field Sheet

31. Parking Indicators: Duration
T
x
x
N
IXN
D


)**(

32. Parking Indicators: Turnover
SS
T
TP
N
TR
*


33. Table 12.8 Summary Data for an Entire Study Area Parking Survey
Max. Accumulation = 1410 Veh.
Occupancy, O = 1410/1500 * 100 = 94%

34. Table 12.8 (continued) Summary Data for an Entire Study Area Parking Survey
Areawide total (Sum)= 2119 parkers

35. Example Analysis Summary
 Tables 12.7 and 12.8
 Avg. Duration, D = 1.12 hr/veh
 Turnover rate, TR = 0.2 veh/stall/hr
 Max. Accumulation = 1410 veh.
 Occupancy, O = 94 %

36. should be 1
Another
Example

37. Another
Example
Sum = 67

38. Off-Street Parking Accumulation
 Counts of entering and departing vehicles
recorder by 15-min interval
 A starting count of occupancy in the facility
 Accumulation = Starting + Entering - Departing

39. 3. Parking Facility Design
 Cost: (lot: Above G: UG)- (1:5:10)
 3 Key design objectives:
1. Convenient and safe
 Proximity to major destinations
 Adequate access/egress facilities (Including
reservoir space)
 Simple and efficient circulation system
 Adequate stall dimensions
 Basic security (veh. theft, personal crime…)

40. Key design objectives (cont.)
2. Space-efficient & economical to operate
 Maximize parking capacity
 Minimize wasted space
3. Compatible with its environs.:
 Architectural beauty
 No visual or auditory disruption

41. Parking Dimensions
 Design vehicles: large & small (Fig. 12.7).
 Parking stall width: Table 12.9
 Parking stall length & Depth:
 Length Large: 221 inch (5.62 m)
 Length Small: 181 inch (4.60 m)
 Depth is 90o projection of stall length
 Aisle width = f (angle, aisle directions)
 Parking modules (Fig. 12.8 & Table 12.10)

42. Figure 12.7 Design Vehicles for Parking Design

43. Table 12.9 Stall Width Design Criteria for Various Parking Classifications

44. Parking Modules
 Definition: basic layout of one aisle with a set
of parking stalls on both sides of the aisle.
 For 900 stalls, 2-way aisles used.
 Modules dimensions: Fig. 12.8/Table 12.10
 Four different layouts
 A single set of stalls against a wall (W1)
 Both sets of stall butt up @ walls (W2)
 One set of stalls @ a wall, other interlocked (W3)
 Both sets interlocked with adjacent module (W4)

45. Figure 12.8 Dimensional Elements of Parking Modules

46. Table 12.10 Parking Module Layout Dimension Guidelines

47. Table 12.10 (continued) Parking Module Layout Dimension Guidelines

48. Figure 12.9 Various Layouts for Integrating Small-Car and Large-Car Stalls in Parking Facilities

49. Planning Models (Gross Area)
 Parallel Parking 27 sq. m.
 300 Parking 34
 450 Parking 30
 600 Parking 27
 900 Parking 23

50. Figure 12.10 Parking Garage Circulation Systems

51. Figure 12.10 (continued) Parking Garage Circulation Systems

52. HW # 7 problems
 12-1: parking generation rates
 12-6: License plate survey