When sensors in a car detect a sudden, violent stop, they fire a tiny chemical charge inside the steering wheel or dashboard. That charge sets off a controlled mini-explosion that produces a burst of nitrogen gas, which races out and inflates the nylon airbag almost instantly. The whole thing takes about 25 milliseconds - faster than a single blink.
The bag has to be quick. In a crash, a driver’s head can fly forward and hit the wheel in less than a tenth of a second. Airbags can pop out at speeds up to 200 mph to beat you to it. They then deflate almost immediately through tiny vent holes so you aren’t pinned against a giant balloon.
Airbags were first added to production cars in the 1970s and became standard equipment by the 1990s. They aren’t a replacement for a seatbelt - the two work together. The belt holds you in place, and the airbag cushions whatever still hits the dashboard.
