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 having traffic control devices that are not currently being recognized by some approaching motorists. Locations should be identified by patterns of crashes related to lack of driver recognition of the traffic control device (e.g., right-angle crashes related to stop sign violations).
This photo shows the use of a wide stop bar on the minor approach to an intersection within a horizontal curve.
Photo by: FHWA
Providing visible stop bars on minor road approaches to unsignalized intersections can help direct the attention of drivers to the presence of the intersection. Where a stop bar is already in place, provision of a wider stop bar may be considered.
Identify appropriate intersection approaches that would benefit from its use. The strategy is expected to be especially effective when applied on approaches where conditions allow the stop bar to be seen by an approaching driver at a significant distance from the intersection. This strategy is appropriate for locations with a pattern of angle crashes associated with stop sign violations where approaching drivers may not realize that an intersection is present until it is too late to stop.
This strategy can be implemented quickly, typically in less than 3 months.
Costs for implementing this strategy are nominal. An agency's maintenance costs may increase.
TRIED: One limited study has indicated that installing stop bars (or wider stop bars) on minor road approaches may reduce crashes by up to 19% and reduce right-angle crashes by up to 47%.
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