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
Complex unsignalized intersections with a high frequency of crashes related to turning vehicle positioning (e.g., sideswipe crashes).
This diagram shows how path markings could be used to assist drivers at a slightly offset unsignalized intersection.
At most intersections, pavement markings are provided on the intersection approaches, but the pavement markings end near the stop line. Rarely are pavement markings extended into or continued through intersections. At complex intersections, however, it may be beneficial to provide motorists with additional information to help with vehicle positioning through the intersections. In particular, it may be desirable to extend pavement markings through intersections that have offset approaches, are skewed, have multiple turn lanes, or are located at unsignalized ramp terminals. This approach is especially useful for delineating vehicle turning paths through an intersection. The MUTCD provides guidance on extending pavement markings through intersections.
Determine which maneuvers drivers are having trouble performing, and define and mark the appropriate turning paths. This may require extensive review of individual crash reports, as well as observations and measurements at a site.
Proper maintenance of the markings will also be important to the success of this strategy.
If too many markings are extended through the intersection, the intersection could become very confusing for drivers.
In cases where snow and ice collect on the road, the effectiveness of the markings may be reduced.
The implementation time for providing turn path markings could be 3 months or less.
The costs involved in providing turn path markings are minimal. Agencies may experience additional maintenance costs.
TRIED: The safety effectiveness of extending pavement markings through intersections has not been evaluated.
This strategy can be used in conjunction with most other strategies for improving safety at intersections.
Highway agencies may need to adopt a policy for extending pavement markings through intersections. Guidance is provided in the MUTCD.
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