Jersey barrier

A Jersey barrier, Jersey wall, or Jersey bump is a modular concrete or plastic barrier employed to separate lanes of traffic. It is designed to minimize vehicle damage in cases of incidental contact while still preventing vehicle crossovers resulting in a likely head-on collision. Jersey barriers are also used to reroute traffic and protect pedestrians and workers during highway construction. They are named after the U.S. state of New Jersey, which first started using the barriers as separators between lanes of a highway in the 1950s.

The barriers are also known as a K-rail, a term stipulated in the California Department of Transportation specification for temporary concrete traffic barriers.

Over time, different variants were created. Taller variants, such as the Ontario tall wall, proved more effective at stopping vehicles and had the added advantage of blocking most oncoming headlights. More modular variants, including plastic water-filled barriers, have been created.

Development and use

Although it is not clear exactly when or where the first concrete median barriers were used, concrete median barriers were used in the mid-1940s on U.S. Route 99 on the descent from the Tehachapi Mountains in the Central Valley south of Bakersfield, California. This first generation of concrete barriers was developed to minimize the number of out-of-control trucks penetrating the barrier and eliminate the need for costly and dangerous median barrier maintenance in high-accident locations with narrow medians.