Impact attenuator

[3] Impact attenuators are usually placed in front of fixed structures near highways, such as gore points, crash barrier introductions, or overpass supports.The "Fitch Highway Barrier System" was invented by race car driver John Fitch after the 1955 24 Hours of Le Mans race when his co-driver, Pierre Levegh rear-ended Austin-Healey driver Lance Macklin at high speed, launching his car through the air and into the spectator's area.As a proof of concept Fitch used liquor barrels filled with sand to create the necessary impact attenuation, then personally crashed reinforced vehicles into them while recording with a high speed camera to capture the rate of deceleration.Fitch barriers are often found in a triangular arrangement at the end of a guard rail between a highway and an exit lane (the area known as the gore), along the most probable line of impact.Their main benefit is in their reusability; some attenuators can automatically return to their original position after a crash,[9] while others require minimal repairs.This is because TMA vehicles are designed to absorb the energy of the impact, while firetrucks are too rigid and can cause severe injuries or death.
Crash Cushion on motorway
A crash cushion installed on a motorway exit in Italy
A water-filled attenuator, as seen in Auckland, New Zealand
Fitch barriers in Canada
A telescoping crash cushion near Tanforan Shopping Center in San Bruno, California
A truck-mounted attenuator (TMA) in New Zealand
motor vehiclecollisionkinetic energyhighwaysgore pointscrash barrieroverpassMomentum transferMaterialdeformationcrumple zoneFrictionrace car driverJohn Fitch1955 24 Hours of Le Mans racePierre LeveghAustin-HealeyLance Macklinone of the worst accidents in racing historystrafingWorld War IIguard railhighwayTanforan Shopping CenterSan Bruno, CaliforniaNew Zealandrailcar bufferssnow plowsUnited StatesAASHTONational Cooperative Highway Research ProgramFederal Highway AdministrationShock absorberTraffic barrierSAFER barrierThe Salt Lake Tribune