An airbag is a vehicle safety device that protects the driver and the passengers in case of a car crash. It consists of a nylon bag coated in neoprene, initially deflated and folded back on itself. It can be installed at the centre of the steering wheel, in front of the front seat passenger, on the lower side of the dashboard and to the sides of both front seats. The airbag is made of a system of sensors that detect sudden changes in speed. In case of violent impact an electrical signal is processed by a control unit and sent to a detonator that is placed in the inflation system. At this point, the air bag instantly inflates with an inert pre compressed gas: nitrogen. To cushion the impact, after having slowed the forward movement of the passengers, the airbag gradually deflates through holes that are placed in the back of the bag.
The airbag was invented in 1952, and patented in 1953, by the American engineer John Hetrick. The first production car with an airbag was the Oldsmobile Toronado in 1973. Market acceptance was initially not positive and International automakers casted doubt on the effectiveness of the device. Starting from the '80s the airbag started to be recognized as a supplement to road safety, to be used exclusively with the seat belt: luxury brands offered life-saving cushions on their high-end cars. After doubts were confounded, in the 90s and in 2000 airbags became commonplace on even smaller-engined vehicles and on mass-market cars. In 2006 the first bike with a fully-integrated airbag was introduced to the market. The production of airbags is nowadays constantly growing and is an integral part of the commercial offer of leading international car manufacturers. Some car brands are testing external airbags that inflate outside of the car to reduce the impact protect pedestrians.