In an impact of sufficient severity, the airbag sensing system detects that the vehicle is in a crash. For both frontal and side impact airbags, the sensing system triggers a release of gas from the inflator, which inflates the airbag. The inflator, airbag and related hardware are all part of the airbag modules inside the steering wheel and the instrument panel. For vehicles with side impact airbags, the modules are located in the side of the front seatbacks closest to the door or the ceiling of the vehicle, near the side windows.