1. MOTOR VEHICLES AND PARKING
Sustainable Transportation
1 March 2013

2. Outlines Designing for Cars Design Guidance Modeling Traffic
Parking Studies
Parking Management

3. Introduction Change Perception of Driving:
Never insinuate that motorists are bad people
Don’t go to extremes
Focus on positive
Costs of driving are largely hidden

4. Introduction Todd Litman (VTPI) summarized the costs of driving:
Vehicle Ownership
Vehicle Operation
Travel Time
Crash
Parking
Congestion
Road Facilities
Land Value
Traffic Services
Air Pollution
Greenhouse Gas
Noise
Resource Externalities
Barriers
Land-use Impacts
Water Pollution
Waste

5. Designing for Cars Four Simple Rules Design follows from context
Speed kills
You cannot build your own way out of congestion
Making cities work for cars first requires making cities delightful for pedestrians

6. Designing for Cars Design follows from context.
Proper street design varies by land use context

7. Designing for Cars Speed kills. Impact force of crash varies by
the mass of the object
the square of its velocity
Source: Western Australian Police

8. Designing for Cars You cannot build your way out of congestion.
Congestion is merely an equilibrium point of the transportation market.
More travel lanes offered, more people would take advantage of them.
Traffic engineers should partner with land planners and real estate economist to develop optimal accommodation for the car.
TE: Better street connectivity.
LP: Concentrate employment and retails around transit.
RE: Shrink the project or reduce density

9. Designing for Car
Making cities work for cars first requires making cities delightful for pedestrian.
Cars consume large space for driving and parking.
Cars should be accommodated but not at the expense of the pleasure of walking.
Parking is shared and managed so spaces are readily available.
Streets are never too wide to walk across comfortably.
Protected pedestrian crossing are available.
Sidewalk are gracious, landscaped and buffered from fast moving traffic.
Building oriented to the street, not the parking lot.
Density is increased to the point at which the needs of daily life are in walking distance.

10. Design Guidance Design Vehicle Speed-control vehicle Design vehicle
Non-motorized vehicle
Setting the design vehicle too low:
Goods delivery may be delayed and cause congestion.
Emergency service providers cannot afford to lose time.
Tight space do not allow future transit network.

11. Design Guidance Design Speed
Maintaining appropriate urban driving speeds:
Travel lanes that accommodate the appropriate design vehicle at the target speed but no wider than they have to be.
No shoulders between travel lanes and curbs.
No superelevation.
On-street parking.
Tight corner radii at intersections.
Appropriate signalized intersection and synchronization to the design speed.
Vertical shifts.
Bicycle facilities.

12. Design Guidance Lane width Number of lanes Intersection design
Corner sight distance
Corner radii
Left-turn lanes
Curb extensions
Access management and driveway design
Grade separations
Traffic calming

13. Modeling Traffic The Four-Step Travel Demand Model Trip Generation
How many trips are generated in each analysis zone?
Trip Distribution
Where are these trips coming from or going to?
Mode Choice
What modes are used for individual trips?
Route Assignment (Traffic Assignment)
Which path each trip will take?

14. Modeling Traffic Trip purpose Zone-based travel Homogeneity Mode bias
Travel time
Parking parameters

15. Modeling Traffic i j Pj, Aj Pi, Ai i j Tij, m1 Tij, m2 Tij, m3 i j Tij
Trip Generation i j
Pj, Aj
Pi, Ai
Modal Split
(Mode Choice) i j
Tij, m1
Tij, m2
Tij, m3
Trip Distribution i j
Tij
Tji
Tjy
Tyj
Txi
Tjx
Traffic Assignment i j

16. Parking
Parking is one of the three essential elements in urban transportation

17. Types of Parking Facilities
Financial
owner-supplied
commercial parking
Physical
On-Street Parking Facilities
Off-Street Parking Facilities
Parking Lots
Parking Structure

18. Purpose of Parking Studies
To establish parking policy and parking regulations.
To check physical needs for revising or increasing the existing parking supply.

19. Glossary Space-Hour: Unit of Parking Utilization
Parking Volume: Demand for a parking facility in a given period of time
Parking Accumulation:
Parking Load: Area under a cumulative curve between two points of time
Parking Duration: Duration that a vehicle is in a parking space
Parking Turnover: Average parking duration for a parking space, equals to parking volume divided by the total number of parking spaces.

20. Data Collection Inventory of Existing Parking Facilities
Types and number of parking spaces
Time of operation
Owner
Parking fees and collection system
Other regulations
Other information

21. Data Collection 7 9 5 8 1 2 3 4 6 10 Parking Facility Block and Curb
Numbering System 7 9 5 8 1 2 3 4 6 10
Parking Facility 3 7 11 2 6 10 1 5 9 4
Block and Curb 8

22. Data Collection Collection of parking data
Accumulation – accumulated parking vehicle counts during all operating hours.
Turnover and Duration – sampling license plate survey of parking vehicles in a parking lot during a given period of time.
Turnover, T =
number of different vehicles parked
number of parking spaces

23. Parking Data Record
Spaces Available, Number of Parking & Daily Turnover by Type of Facility
Block
Space Available
# of Vehicles Parking
Daily Turnover
Curb
Lots
Garages
Total
Legal
Illeg
021 17
117 12
129
6.9
022 28
106 36
170
264
292 47
615
9.4
2.8
1.3
3.5
023 72 63
135
373 20
127
520
5.2
2.0
3.7

24. Parking Data Record
Other Parking Usage Characteristics by Number of Vehicles Parked and Time Used in Different Facilities
Block
Legal Curb Space
Illegal Curb Space
Total Curb Space
Lots
Garages
Total
Veh Parked
Veh Hours
040
120 67 10 6
130 73
320
1500 52
520
502
2093
041 40 80 62

25. Data Collection
Identification of Parking Generators, e.g. shopping mall and train station.
Parking Rate Manual – same format as Trip Generation Manual
Collection of Information on Parking Demand is usually conducted by garage (or parking lot) interview. Questions may include origin, destination after parking and trip purpose.

26. Parking Data Record
Comparison of Observed Vehicle Hours of Parking, Space Hours Available and Deficiency of Surplus in Existing Capacity
Block
Total Observed Veh-Hours of Parking
Overtime
Veh-Hours of Parking
Veh-Hours of Parking with No Illegal Parking
Space-Hours Capacity of Available Legal Space
Space-Hours Capacity
Deficiency
Surplus
051 40 15 25 30 - 5
052 2 23 20 3
053 60 10 50

27. Estimation of Parking Requirement
Laws and Regulation
Building Codes
Municipal Codes
Parking Rate – Apply the same principle with trip generation rate
Standards
Surveys
Parking Analysis

28. Parking Analysis Demand Supply where D = parking demand, space veh-hr
N = number of types of parking vehicles
ni = number of parking vehicles type i
ti = average parking duration of type i, hours
Supply
where
S = parking supply, space-hr
N = number of parking spaces
f = coefficient of parking efficiency
ti = parking service hours

29. Parking Analysis Example
A parking lot owner noticed that 20% of entering vehicles could not find a parking space and left the building during service hours 8:00 – 18:00. A ticket analysis showed that 60% of parked vehicles were employers’ with average duration of 9 hours. The rest are customers’ vehicles with average duration of 2 hours. Currently 200 vehicles per day parked in the facility. Further, it was later learned that 20% of vehicles unable to find a parking space belonged to employees and the rest belonged to customers. Determine how many parking spaces should be added. Assume coefficient of parking efficiency 0.80.

30. Parking Analysis Example (cont’d)
Employees parked = (0.6 x 200) x 9 = 1080 space-hr D1
Customers parked = (0.4 x 200) x 2 = 160 space-hr D2
Unable to find parking space = x 0.2 = 50 veh
Employees unable to find parking space = (0.2 x 50) x 9 = 90 space-hr D3
Customers unable to find parking space = (0.8 x 50) x 2 = 80 space-hr D4
Total parking demand (D1) + (D2) + (D3) + (D4) = 1410 space-hr
200
0.8

31. Parking Analysis Example (cont’d)
Existing parking supply = = space-hr
Shortage = 1410 – 1240 = 170 space-hr
0.8 x 10 x N = 170
N = 21.25
Additional parking spaces needed 22 spaces

32. Parking Dimensions

33. Parking Dimensions
Computer-Aided Design Package
PARKCad
AutoTurn

34. Pedestrian-Friendly Environment
Promoting Sustainable Transportation
Parking lots along the full length of the street front are not pedestrian-friendly.
Parking lots located behind shops and offices are more preferred.
“No parking shall be located between the building and the front property line. On corner lots, no parking shall be located between the building and either of the two front property lines.”
The SeaTac Municipal Code, Section C

35. Parking Innovations

36. The High Cost of Free Parking

37. Parking Requirements versus Parking Restraints
“Parking demand is defined as the accumulation of vehicles parked at a given time as the result of activity and given site”
R. Weant & H. Levinson
Parking Provision Strategies
Copy other cities
Consult ITE Data
“Off-street parking does eat up a tremendous amount of land, but minimum parking requirements lead planners and developers to think that parking is a problem only when there isn’t enough of it”
Donald Shoup

38. The “Commons” Problem
“The commons has come to serve as a paradigm for situations in which people so impinge on each other in pursuing their own interest that collectively they might be better off if they could be restrained, but no one gain individually by self-restraint…” Thomas Shelling “Free curb parking is an asphalt commons: just as cattle compete in their search for scarce grass, drivers compete for scarce curb parking spaces. Drivers waste time and fuel, congest traffic, and pollute the air while cruising for curb parking, and after findinga space they have no incentive to economize on how long they park.” Donald Shoup

39. Parking “Requirement” Adverse Effects
Skew travel choice
Raise house/office prices
Hidden costs in merchandise
Barrier to economy growth

40. Vicious Cycle of Free Parking
Parking Generation Rates
Survey at all sites with no classification.
Minimum Parking Requirement
Max observed = Min required
Ample Free Parking
Driving is encouraged.
Trip Generation Rates
High trip rates reported.
Transportation System Design
Provide large capacity to satisfy demand.
Urban Sprawl
Low density regulation spreads activities. More driving/parking demand.
Derived from Shoup, D.,
“The High Cost of Free Parking

41. Parking Management Strategies
Park Once.
Create a commercial parking benefit area.
Invest meter revenues in areawide improvements and TDM.
Create residential benefit areas.
Provide universal transit passes.
Unbundle parking costs.
Require parking for carsharing vehicles.
Require parking cash-out.
Removing minimum parking requirements.
Fund parking facilities with user fees and revenue bonds.

42. To Park or Not To Park
Hermann Knoflacher and his walkmobile “Gehzeug” illustrated the problem of excessive automobile usage

43. Homework
A parking has 2,000 parking spaces. There were 3,000 cars entering between 8:00 – 18:00. The study showed that 20% of these cars parked for 2 hours, 30% parked for 4 hours and the rest parked for 8 hours. If, on average, 10% of spaces were vacant, find this lot’s parking efficiency factor.