In certain types of side collision the side airbags (front and rear^*) are triggered on the impact side of the Audi A4 Fig. 1. Further airbag systems may also be triggered, depending on the circumstances.

When the system is triggered, the airbag is filled with propellant gas.

In order to provide the desired extra protection in an accident, the airbags have to inflate extremely rapidly (within fractions of a second). The airbag releases a fine dust when it inflates. This is quite normal and does not mean there is a fire in the Audi A4.

When fully deployed, the airbags cushion the impact for the occupants and help to reduce the risk of injury to the whole upper part of the body (i.e. the chest, stomach and pelvis) on the side facing the door.