Parking

Article

Although most transportation research, published articles, and popular discussion focus on the movement of motor vehicles through roads and intersections, cars actually sit in parking spaces 95 percent of the time.  In many urbanized areas, parking assumes 20-40 percent of the land surface area. 

The design and location of parking is one of the most important elements of great streets.  The quantity, location, management, cost, and design of parking depend heavily on the adjacent land use the parking is serving.  For example, parking design in downtown areas is very different than parking at a suburban office complex.  Still, there are several parking principles that permeate all land uses.

Ensure on-street parking. On-street parking is the most valuable type of parking for several reasons: 

• It creates a physical and psychological buffer between pedestrians on the sidewalk and moving traffic.
• It presents the best access to the front door of retail, residential, and commercial destinations. 
• It limits the need for off-street parking facilities. Off-site parking facilities use valuable land, require additional curb cuts through the pedestrian realm for access, and present challenges to creating good urban design.  Additionally, in urban areas, off-street parking facilities can be extremely expensive. 
• On a per space basis, on-street parking takes up less land area than other forms of parking because the ramps, driveways, and aisles needed in parking lots and structures are absorbed by travel lanes themselves.

Place parking behind buildings. Fronting streets with buildings (as opposed to parking) cetes a more interesting,  pedestrian-friendly environment. Locating parking behind buildings also allows driveways/access points to be placed on lower volume side streets, presumably with fewer pedestrians. Placing driveways (including those to parking lots) on side streets creates a more continuous pedestrian frontage, reduces the potential for pedestrian-motor vehicle conflicts, and eliminates mid-block left hand turning movements on the higher volume street - a leading cause of mid-block congestion.

Encourage shared parking. Peak parking demand for adjacent land uses often occurs at different times of the day.  For example, a bank and a neighboring movie theater could feasibly share spaces as their parking demand peaks at different times.  Although such arrangements are more common in Parking, shared parking can be implemented in all place types.  Shared parking decreases the need for off-street parking spaces and lots, which imparts many of the benefits mentioned above.  See the Urban Land Institute’s Shared Parking  (Smith. Shared Parking, Second Edition. ULI and the International Council of Shopping Centers. 2005) for more information about shared parking.

Source: ADAAG

Provide handicapped parking. Federal law requires that handicapped parking be provided in all designated parking areas.  The Americans with Disabilities Act (ADA) sets guidelines for handicapped parking requirements for all new construction.  The minimum number of required handicapped spaces is based on the total number of spaces in the parking facility, as outlined in the figure at right. 

The location of these spaces is also regulated, as explained below in the ADA Accessibility Guidelines: 

“Accessible parking spaces serving a particular building shall be located on the shortest route of travel from adjacent parking to an accessible entrance” (ADAAG 4.6.2).

Although there are established national standards, individual municipalities often set their own standards for handicapped parking.  A 1990 study of retail shopping centers found that the number of handicap spaces in commercial areas varied between 0.7% and 2.0% of the total parking supply (Weant and Levineson. Parking Spaces. McGraw Hill. 1999).

Include bicycle parking. Although automobiles typically come to mind when parking is mentioned, great streets have provisions for all modes, including adequate and secure bicycle parking.  There are no national standards for bicycle parking, and local requirements vary widely.  One of the most convenient methods for establishing appropriate bike parking design is to view the ordinances of municipalities with high bike mode shares.  The city of Madison, Wisconsin, for example, provides excellent guidelines on the appropriate quantity, location, and design of bike parking.  The city of Portland, Oregon also has an excellent web page with guidelines for installing bicycle parking.

Minimize supply. Parking is often oversupplied, which creates a number of design challenges.  A 2003 study of 42 parking lots during the holiday season found that the average occupancy was less than half (Gould. “Parking: When Less is More.” Transportation Planning, Vol.28, No.1. Transportation Planning Division, APA. Winter 2003). 

Source: City of Seattle

Retail shopping centers with massive parking facilities that are rarely (if ever) full are a common sight in most communities.  Parking is oversupplied because the minimum parking requirements for residential and commercial development is often set at the annual maximum expected demand, leaving excess parking for much of the year. 

Ensure delivery parking. Delivery parking must be provided in most, if not all, place types, but is particularly important in areas with a high concentration of retail shops and restaurants.  Alleys are ideal locations for temporary truck parking, allowing back door delivery access away from customer parking and entrances.  When alley use is not feasible, special loading zones can be designated.  The image at right is an example of signage used in a loading/unloading zone.

Parking for Civic and Educational Corridors:

Educational corridors have unique parking issues due to the high land values typically seen in and around university campuses.  Because land values tend to be high in these areas (studies suggest $400,000 to $2 million per acre) increasing the area's parking supply often entails converting surface lots to parking structures. Transportation and Sustainable Campus Communities by Will Toor and Spenser Havlick discusses the enormous expense universities incur by switching to structured parking. 

Universities should consider the following potential problems before converting surface parking to structured parking:

1. Loss of surface spaces - greatly reduces net gain in supply;

2. High space demands - drive aisles, ramps, columns, and stairwells needed in parking structures reduce the number of spaces per acre;

3. Discrete intervals of supply - variations in the amount of parking supplied are limited to levels;

4. High costs - $125 to $200 per month for each additional space; and

5. Construction delays - no parking supply during construction.

The images below were taken in close proximity on the campus of the University of Colorado, Boulder. Switching from surface parking to structured parking provides land for other uses, but at a high cost to a campus community.

Credit: Charlier Associates, Inc.

Credit: Charlier Associates, Inc.

Several universities have conducted research to compare the cost-effectiveness of providing free or highly discounted transit passes and creating more parking (e.g. the University of Washington's U Pass Annual Report). 

Research reveals that on a per student basis, providing transit passes in lieu of additional parking is two to three times less expensive, without even considering other benefits such as reductions in traffic congestion on the adjacent roadway network.

Resources

PDFs:

• Madison Bicycle Parking Ordinance
• The University of Washington's U Pass Annual Report

Links:

• ADA parking requirements
• Portland bicycle parking guidelines