Impact attenuator

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An impact attenuator, also known as a crash cushion or crash attenuator, is a device intended to reduce the damage done to structures, vehicles, and motorists resulting from a motor vehicle collision. Impact attenuators are designed to absorb the errant vehicle's kinetic energy and/or redirect the vehicle away from the hazard.^[1]

Impact attenuators, typically composed of sand or water filled barrels or modules, are typically placed in front of fixed structures near freeways, such as gore points, Jersey barrier introductions, or overpass supports. Temporary versions can be used for road construction projects.

Truck-mounted versions, similar to railcar buffers, can be deployed on vehicles that are prone to being struck from behind, such as snow plows and road construction vehicles.

In the United States, impact attenuators are tested and classified according to Federal Highway Administration NCHRP Report 350. Classification is based on the maximum speed of a vehicle during a collision for which the attenuator is designed.