An improved inflatable passenger side air bag safety device for motor vehicles for detecting the presence or absence of a passenger positioned on or in front of a particular passenger vehicle seat. The safety device comprises a control unit for the intelligent triggering of the propellant charge for the air bag when a triggering event is detected, such as an impending collision, and the presence of a passenger is also detected. The control unit receives signals from a pair of switches, electrically connected in parallel to one another, including a first seat switch for detecting the presence or absence of a sitting passenger and a second foot switch for detecting the presence or absence of a standing, kneeling, or sitting passenger in the region in front of the vehicle seat. In the preferred embodiment both switches are flat, contact type switches, each having a broad surface area and are activated when subjected to the weight of a passenger from above. An acceleration sensor is also connected to the control unit for signaling the event of an impending collision. In an alternate embodiment the foot switch is a condenser-type switch in the form of a metallic screen interwoven within the floor carpet and detects fluctuations in the magnetic and electric fields corresponding to the presence or absence of a passenger positioned over the floor carpet. The air bag associated with the vehicle seat is caused to be activated during a triggering event if either of the seats switch and/or foot switch are activated by a passenger.