A New Jersey barrier (in English Jersey barrier) is a safety barrier, generally made of concrete, used as a separator of traffic flows, as protection in military installations or to provisionally delimit areas under construction.

Although there are some slight variations on its original design, a standard New Jersey barrier is a single- or double-sided prefabricated rigid structure constructed of reinforced concrete. It has a minimum width at its tip of 0.15 meters and an approximate weight of 1700 kg. Its length is 275 cm, its width is 63 cm and its height is 80 cm.

Its main advantages are high resistance to shock and the occupation of a very small space. There are also mobile New Jersey barriers made of plastic material, white or red, fillable with water or sand.

These barriers were first installed in the 1950s in the New Jersey region of the United States,[1]​ to divide multiple lanes of a highway, and this is where their name comes from.

They were incorporated in Spain around 2001 for the protection of highways and highways. These are made of solid reinforced concrete, with characteristics of evacuating water from the road and anchoring to the ground. Starting in 2020, coinciding with the SARS-CoV2 epidemic, they are used in the city of Barcelona (Spain) to protect the terraces of bars and restaurants extended to the road during the pandemic.