An impact attenuator, also known as a crash cushion, crash attenuator, or cowboy cushion, is a device intended to reduce the damage to structures, vehicles, and motorists resulting from a motor vehicle collision. Impact attenuators are designed to absorb the colliding vehicle's kinetic energy.

They may also be designed to redirect the vehicle away from the hazard or away from roadway machinery and workers.

Impact attenuators are usually placed in front of fixed structures near highways, such as gore points, crash barrier introductions, or overpass supports.

Temporary versions may be used for road construction projects.

Truck-mounted versions (truck mounted attenuators (TMA)), similar in some ways to railcar buffers, can be deployed on vehicles that are prone to being struck from behind, such as snow plows and road construction or maintenance vehicles.

Work zone regulations often specify a minimum buffer distance between the attenuator truck and the work area, and a minimum mass for the truck, to minimize the chances that the truck will be pushed forward by a crash into the workers or machinery.

This is especially important in mobile work zones where the truck's parking brake may not be engaged. The truck may also be in movement (albeit slower than the vehicles that could crash into it).