The main parts of an airbag are the airbag, sensor, accelerometer, inflation system, and propellant inflators. Some
systems may also have an on/off switch, which allows the airbag to be
deactivated. The airbag fully inflates within a fraction of a second, then deflates. The size of an airbag when fully inflated differs between cars and manufacturers. When an airbag is inflating the average maximum speed is 200 mph. The sensors in the airbag would be the most likely to fail of any other part of the airbag. This is because sometimes the accident occurs at a different part of the car than where the sensor senses.