US Patent 7794174 Crash impact attenuator systems and methods

A reusable energy-absorbing crash attenuator comprises a base, a rail disposed on and extending along a length of the base, and a plurality of energy absorbing modules slidably disposed on the rail. Each of the energy absorbing modules comprises a first module portion and a second module portion which are attached together. Each of the module portions comprise plastic, preferably high density polyethylene (HDPE), and have a combination of concave and convex curvature. A plurality of fender panels are disposed in adjoining end-to-end fashion along each side of the length of the crash attenuator. The fender panels are arranged to slide together in telescoping fashion upon impact of the crash attenuator by a vehicle.