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
Unsignalized intersections on divided highways. The strategy is particularly appropriate for intersections with patterns of rear-end, right-angle, or turning crashes related to lack of awareness by the driver on the minor road to the presence of the intersection.
Providing dashed markings (extended left edgelines) to define median roadway area at divided highway intersections can help distinguish the median area from the through roadway and, thus, enhance the ability of approaching drivers to be more aware of the presence of the intersection.
Select a combination of marking techniques appropriate to conditions on particular unsignalized intersection approaches on divided highways. This engineering judgment should, where possible, be accompanied by a human-factors assessment of marking needs.
Another key is the ability and commitment of the highway agency to maintain the markings adequately.
This strategy does not require a long development process and can typically be implemented in 3 months or less.
Costs to implement this strategy are nominal. An agency's maintenance costs may increase.
TRIED: The effectiveness of this strategy in reducing crashes has not been satisfactorily quantified.
This strategy can be used in conjunction with most other strategies for improving safety at unsignalized intersections.
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