U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
NCHRP Report 500 / Volume 12: A Guide for Reducing Collisions at Signalized Intersections
Signalized intersections with permitted parking on the approaches that may present a safety hazard either by blocking sight distance or due to parking maneuvers.
Photo by: FHWA
Parking adjacent to turning and/or through lanes on intersection approaches may create a hazard. It can cause a frictional effect on the through traffic stream, can often block the sight triangle of stopped vehicles, and may occasionally cause the blocking of traffic lanes as vehicles move into and out of parking spaces. Restricting and/or eliminating parking on intersection approaches can reduce the workload imposed on the driver and limit additional collision opportunities. Parking restrictions can be implemented through signing, pavement markings, or restrictive channelization. Restrictions can be implemented for specific times of day or specific vehicle types. Enforcement of parking restrictions, accompanied by public information, including towing offending vehicles, is a necessary component of this strategy.
Parking regulation signs need to be posted conspicuously. Consistent and rigorous enforcement of these regulations is necessary as well. Working with owners of adjacent properties to communicate the reasons for prohibiting parking is also essential to achieving success.
The Uniform Vehicle Code does not require use of No Parking signs in some circumstances. Drivers are often not aware of some of the locations where parking is prohibited, however, and signs should be used to convey this information to drivers.
Adjacent land owners, particularly commercial businesses, may be opposed to the removal of on-street parking.
Removal of parking requires a commitment to enforcement through ticketing and towing where needed.
Time to implement parking restrictions is low if no new ordinances are required. Implementation may, however, require passing of ordinances by city councils.
Costs to implement parking restrictions with signing are low. If enforcement is used to help implement the restrictions, costs will be increased.
PROVEN: The Institute of Transportation Engineer's Traffic Engineering Handbook states that, based upon a review of crash data, 20% of non-freeway crashes in cities are in one way or another related to parking. Mid-block crash rates on major streets with parking stalls that are used about 1.0 million hours per year per mile could be expected to decrease up to 75% after parking is prohibited.
An Australian study showed that banning parking adjacent to an intersection resulted in an average decrease in crashes of 10%. ITE reports a 49% decrease in all crashes when parking is restricted near an intersection.
Restriction of parking is compatible with most other strategies for improving signalized intersection safety.
Highway agencies should review their traffic engineering and design policies regarding on-street parking to ensure appropriate action is being taken on projects. All stakeholders should be involved from the earliest stages of planning, including owners of adjacent properties and representatives of legislative bodies for the jurisdictions involved.
For more details on this and other countermeasures: http://safety.transportation.org
For more information contact:
FHWA Office of Safety Design
E71, 1200 New Jersey Avenue SE
Washington, D.C. 20590
FHWA Resource Center – Safety and Design Team
19900 Governor's Drive, Suite 301
Olympia Fields, IL 60461