Airbag

Cars have front airbags in the steering wheel and dashboard, and often side, curtain and knee airbags. Airbags are a supplemental restraint system (SRS): they work together with seat belts, not instead of them. Many front airbags have two stages and inflate with different force depending on crash severity and seat position.

Crash sensors send signals to the airbag control module, which fires a gas generator. The bag inflates in about 30 milliseconds and then deflates through vents.

An SRS warning light means the airbags may not deploy in a crash and should be checked promptly. Airbag parts must only be handled by trained people; unplugging connectors with the ignition on can set faults or, in rare cases, trigger a deployment.