- Inventor
- John W. Hetrick (concept, 1953) and Allen Breed (crash sensor, 1968)
- First used
- 1973 — Oldsmobile Toronado (US fleet pilot); 1974 — Buick, Cadillac, Oldsmobile retail
- Origin
- United States and Germany (parallel development at GM and Mercedes-Benz)
How it came to be
Industrial engineer John Hetrick filed the first automotive airbag patent in 1953 after a near-miss with his family. The technology wasn't viable until Allen Breed invented the first electromechanical crash sensor in 1968. GM launched the first production airbag (the Air Cushion Restraint System) in 1973, but high cost and false deployments killed the program by 1977. Mercedes reintroduced the modern driver airbag on the 1981 S-Class, this time integrated with the seatbelt as a 'supplemental restraint system' (SRS). Passenger, side and curtain bags followed through the 1990s.
Key milestones
- 1953John Hetrick patents the 'safety cushion assembly for automotive vehicles.'
- 1968Allen Breed invents the ball-in-tube crash sensor — the trigger that made airbags practical.
- 1973GM offers the Air Cushion Restraint System on the Oldsmobile Toronado.
- 1981Mercedes-Benz W126 S-Class launches the first modern driver airbag in Europe.
- 1988Chrysler makes driver airbags standard across its US lineup.
- 1994Volvo 850 introduces side-impact airbags.
- 1998Toyota Avensis debuts curtain (head-protecting) airbags.
- 2009US law (FMVSS 208) requires advanced dual-stage front airbags in all new cars.
- 2020Honda debuts a tent-shaped front airbag designed to catch the head in angled crashes.
Driver and passenger frontal airbags are mandatory in new US cars under FMVSS 208 (since 1998). The EU does not mandate airbags directly but Euro NCAP scoring effectively requires them.
How they fire
Accelerometers detect a crash pulse. A controller decides whether to fire and which bags to deploy. A solid propellant (sodium azide on older cars, modern guanidine nitrate) burns to inflate the bag in 20–30 ms. The bag immediately vents through ports so you don't bounce off it.
Front airbags
Driver bag deploys from the steering wheel hub; passenger bag from the upper dash. They protect against forward impact with the wheel, dash and windshield. Modern bags are dual-stage — softer for low-speed crashes and small occupants, full power for serious impacts.
Side and curtain airbags
Thorax airbags in the seat backs cushion the chest in side impacts. Curtain airbags drop from the roof rail to protect heads from window-frame intrusion and from being thrown out in a rollover. The Volvo XC90 and modern Mercedes also offer center airbags between front seats.
Limitations
Airbags supplement seatbelts; they don't replace them. An unbelted occupant in a 35 mph crash hits the deflating airbag at full body weight and is often more injured than if no bag had fired. They also do nothing in pure rollover or under-ride crashes — that's why structure matters.
