When a Collision Occurs

hen a crash occurs, the vehicle rapidly decelerates while its structure absorbs the majority of the crash forces. Unbelted occupants continue to move forward at the vehicle's original speed until the vehicle's interior (the steering wheel, instrument panel, windshield, etc.) stops their movement. Belted occupants come to a more gradual stop by being secured to the vehicle's structure. In severe crashes, even properly belted occupants may come into contact with the vehicle's interior.

Air bags supplement the safety belt by reducing the chance that the occupant's head and upper body will strike some part of the vehicle's interior. They also help reduce the risk of serious injury by distributing crash forces more evenly across the occupant's body.

When there is a moderate to severe frontal crash that requires the frontal air bag to deploy, a signal is sent to the inflator unit within the air bag module. An igniter starts a reaction, which produces a gas to fill the air bag, making the air bag deploy through the module cover. Some air bag technologies use nitrogen gas to fill the air bag while others may use argon gas. The gases used to fill air bags are harmless.

From the onset of the crash, the entire deployment and inflation process takes only about 1/20th of a second, faster than the blink of an eye. Because a vehicle changes speed so fast in a crash, air bags must inflate rapidly if they are to help reduce the risk of the occupant hitting the vehicle's interior.

d

Back

Continue