switch 11 is mounted on the rear side of the cover 0f course it will be appreciated that the bridge areas 14c and 18c may if desired also be superimposed with a dielectric layer sandwiched between the two bridge area layers in a preferred embodiment of this invention rigid backing plates or sheets 20a and 20b may be employed to the rear of the membrane sheets 14 and 18 to provide for easier actuation of the assembled membrane switch 11 the backing members 20a and 20b are preferably a rigid thermoplastic sheet and more particularly a polycarbonate having a thickness of about 1 mm to provide a stable and rigid pressure surface for actuation of the switch if such backing plates or sheets are utilized in the switch the backing plates or sheets can be provided with mounting openings 22 corresponding to the mounting openings on membrane sheets 14 and 18 in a further embodiment of this invention the relatively small bridging areas 14c and 18c may be provided with one or more preferably at least two opposing notches 24 which act to further weaken the thin membrane bridging areas and enhance their ability to rupture during airbag deployment the assembled membrane switch 11 preferably with rigid backing members 20a and 2ob is mounted against the rear or inner surface.