When fully inflated, the airbags reduce the risk of head or chest injury.

Front airbags in inflated condition

The airbag system is designed so that the airbags for the driver and front passenger are triggered in a severe frontal collision.

In certain types of accident the front airbags, side airbags and one of the head-protection airbags may be triggered together.

When the system is triggered, the airbags fill with a propellant gas and open out in front of the driver and front passenger ⇒ fig. 216. In order to provide the desired extra protection in an accident, the airbags have to inflate extremely rapidly (within fractions of a second). The fully deployed airbags cushion the forwards movement of the front occupants and help to reduce the risk of injury to the head and the upper part of the body.

Special openings in the airbag allow the gas to escape at a controlled rate to restrain the forward movement of the occupant's head and torso. Once the impact has been absorbed, the airbag deflates sufficiently for the front occupants to see forward.