Technology
How does an airbag work?
An airbag works by detecting a crash in milliseconds and instantly inflating a cushion to stop your body from hitting the hard interior. A sensor triggers a rapid chemical reaction that fills the bag with gas faster than you can blink.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how an airbag works.
Step by step
- 1Crash sensors detect the sudden, severe deceleration of a collision.
- 2They trigger an igniter that sets off a fast chemical reaction inside the inflator.
- 3The reaction produces a burst of gas that inflates the bag in about 1/20th of a second.
- 4The bag cushions the head and chest, then deflates through vents to absorb the impact.
- 5Airbags are designed to supplement seatbelts, not replace them.
Frequently asked questions
- How fast does an airbag inflate?
- Extremely fast — in roughly 20 to 30 milliseconds, quicker than a blink, because it must deploy before your body moves forward in a crash.
- Why do airbags need seatbelts too?
- Airbags cushion you at the right position and moment; the seatbelt keeps you in that position. Without a belt, an inflating airbag can itself cause injury.
- What inflates the airbag?
- A sensor-triggered chemical reaction rapidly produces gas (often nitrogen) that fills the bag — not stored air, which couldn't deploy fast enough.