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24-hour Road Assistance

How Do Airbags Work?


While airbags are not compulsory, over the last few years they have become more common with most new car manufacturers now fitting at least a driver’s side airbag. A number of models also have passenger and side impact airbags as optional extras. If airbags are fitted, the steering wheel cover and/or dashboard cover of you car will usually have the words ‘airbag’ or ‘SRS airbag’ moulded into them. SRS stands for Supplemental Restraint System, which means that airbags are not a substitute for seat belts.

An airbag is a fabric bag that inflates rapidly when required from the steering wheel centre or dashboard. They are are designed to deploy in moderate/major crashes only and should not deploy in minor accidents. The airbag inflator contains a sealed solid chemical gas generator. In a severe crash electricity flows to the inflator and causes ignition of the gas generator. The gas generator then rapidly burns producing inert gases and small amounts of dust. The inflating airbag then splits open the trim cover, rapidly unfolds and inflates in front of the occupant. This happens in a fraction of a second. After inflation, airbags deflate in under a second and may be pushed aside for occupants to exit.

While airbags significantly reduce the risk of serious or fatal injury in crashes, there are some risks from the deployment of airbags in minor accidents. For this reason modern cars use a range of intelligent sensing functions to ensure that a crash is actually happening, as opposed to hitting an elevated median strip or kerb, or someone reversing into your car in the car park. This reduces the likelihood of airbags deploying in minor crashes.

Owners should refer to their vehicle Owner’s Manual for further explanation of airbag deployment parameters and characteristics. AANT members can also access our Technical Advice Hotline 1300 661 466.

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