Although a recent invention, the history of the airbag goes back over 50 years to 1951. The first patent was applied for by the German Walter Linderer and American John Hedrik. Hedrik's idea was inspired after a road accident while out driving one Sunday afternoon with his family when he had to swerve to avoid a deer in the road and ended up in a ditch. Thankfully, he and his family were unhurt, but the experience began the process whereby many lives would be saved in future by the inflatable airbag. Hedrik's patent was granted in 1953.
Although the major manufacturers also experimented with airbags in the 1950s, it was not until the 70s that their interest became serious, mainly due to the rapid expansion of car use and the associated rise in traffic accidents in the 1960s. The potential use of airbags was given a major impetus in 1969 when the American, Allen Breed designed an effective and cheap crash sensor. Ford tested the use of airbags in 1971, followed by General Motors two years' later. In the mid-70s, General Motors were giving purchasers the option of airbags in several of its models. However, early models were not without their faults and even lead to driver deaths in some instances. The widespread introduction of the airbag was also hampered by the attitude of the major car manufacturers who believed that safety was not a factor which helped to sell cars.
It was not until the late 1980s that airbags became a standard feature when Chrysler began to incorporate them into its models. By the early 1990s most cars were being manufactured with airbags to protect the driver and, within a couple of years, this had been extended to the front passenger seat.
Today, there are two types of airbag of airbag in use. The frontal airbag is built into the area in front of the driver and passenger and protects from a frontal crash. Side impact airbags protect the vehicle occupants from a side impact. In 2006, Honda became the first manufacturer to install airbags in motorcycles.
The basic concept behind the operation of airbags is quite simple. When a vehicle has an impact, it decelerates so fast, the airbag sensors are triggered. This sends power to the heating element in a propellant, causing a chemical reaction that produces a gas, which in turn fills the airbag. A key safety feature is that as soon as the gas expands in the airbag, it begins to cool, causing the bag to deflate as soon as it fully inflates. Obviously, speed is of the essence and an airbag is able to fully inflate in 0.05 of a second following the impact.