a concrete barrier originally developed as a highway median

a angled concrete barrier designed to guide an errant vehicle back to the roadway and guard against hazards.

A low, reinforced concrete wall wider at the base, tapering vertically to near mid-height, then continuing straight up to its top. The shape is designed to direct automotive traffic back toward its own lane of travel and prevent crossing of a median or leaving the roadway. Commonly used on new and reconstructed bridges in place of decorative ballustrades, railings or parapets.

Concrete barrier designed to guide errant vehicles back into the roadway.

a jersey barrier is a concrete barrier that acts as a traffic control device to separate traffic flow.

A Jersey barrier or Jersey wall separates lanes of traffic (often opposing lanes of traffic) with a goal of minimizing vehicle crossover in the case of accidents. It is also used as defense against car bombs.