U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
NCHRP Report 500 / Volume 5: A Guide for Addressing Unsignalized Intersection Collisions
Approaches to unsignalized intersections with patterns of rear-end, right-angle, or turning collisions related to lack of driver awareness of the presence of the intersection.
Photo by: FHWA
The visibility of intersections and, thus, the ability of approaching drivers to perceive them can be enhanced by installing larger regulatory and warning signs at intersections. Such improvements may include stop signs, intersection warning signs, stop ahead signs, pavement markings, and post-mounted delineators. The FHWA Older Driver Highway Design Handbook encourages such improvements to contribute to a better driving environment for older drivers.
Select a combination of regulatory and warning sign techniques appropriate to conditions on particular approaches to unsignalized intersections. This engineering judgment should, where possible, be accompanied by a human factors assessment of the need for regulatory and warning signs.
Another key is the ability and commitment of the highway agency to adequately maintain the signs.
Care should be taken not to overuse traffic signing, as it is likely that drivers will become accustomed to their presence and fail to respond as desired or intended. Agencies should strive to use special signing only where a specific problem or circumstance indicates the need.
This strategy does not require a long development process. Signing improvements can typically be implemented in 3 months or less.
Costs for implementing this strategy are nominal. An agency's maintenance costs may increase.
TRIED: One limited study has indicated that installing larger stop signs may decrease all collisions by up to 19%.
This strategy can be used in conjunction with most other strategies for improving safety at unsignalized intersections.
Signing in conformance with the Manual on Uniform Traffic Control Devices should be provided.
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