Crumple Zone

The crumple zone is a structural feature mainly used in automobiles and recently incorporated into railcars.

Crumple zones are designed to absorb the energy from the impact during an accident by controlled deformation. This energy is much higher than is commonly recognized. A 2000kg car travelling at 60 km/h (16.7 m/s), before crashing into a massive concrete wall, is subject to the same impact force as a front down drop from a height of 14.2m crashing on to a massive concrete surface. Increasing that speed by 50% to 90 km/h (25 m/s) compares to a fall from 32m - an increase of 125%. This is because the stored kinetic energy (E) is given by E = (1/2) mass × speed squared. It increases as the square of the impact velocity.

Typically, crumple zones are located in the front part of the vehicle, in order to absorb the impact of a head-on collision, though they may be found on other parts of the vehicle as well. According to a British Motor Insurance Repair Research Centre study of where on the vehicle impact damage occurs: 65% were front impacts, 25% rear impacts, 5% left side, and 5% right side. Some racing cars use aluminium or composite/carbon fiber honeycomb to form an impact attenuator that dissipates crash energy using a much smaller volume and lower weight than road car crumple zones. Impact attenuators have also been introduced on highway maintenance vehicles in some countries.

An early example of the crumple zone concept was used by the Mercedes-Benz engineer Béla Barényi on the mid 50's Mercedes-Benz "Ponton". This innovation was first patented by Mercedes-Benz in the early 1950s. The patent 854157, granted in 1952, describes the decisive feature of passive safety. Barényi questioned the opinion prevailing till then, that a safe car had to be rigid. He divided the car body into three sections: the rigid non-deforming passenger compartment and the crumple zones in the front and the rear. They are designed to absorb the energy of an impact (kinetic energy) by deformation during collision.

On September 10, 2009, ABC News 'Good Morning America' and 'World News' showed a U.S. Insurance Institute of Highway Safety crash test of a 2009 Chevrolet Malibu in an offset head-on collision with a 1959 Chevrolet Bel Air sedan. It dramatically demonstrated the effectiveness of modern car safety design, over 1950s design, particularly of rigid passenger safety cells and crumple zones.