In an impact of sufficient severity, the airbag sensing system detects that the vehicle is in a crash. The sensing system triggers a release of gas from the inflator, which inflates the airbag. The inflator, the airbag and related hardware are all part of the airbag modules. Frontal airbag modules are located inside the steering wheel and instrument panel. For seating positions with side impact airbags, there are also airbag modules in the side of the seatbacks closest to the door.