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.