<P> This terminology is not related to active and passive safety, which are, respectively, systems designed to prevent accidents in the first place, and systems designed to minimize the effects of accidents once they occur . In this usage, a car Anti-lock Braking System (ABS) will qualify as an active - safety device, while both its seatbelts and airbags will qualify as passive - safety devices . Further terminological confusion can arise from the fact that passive devices and systems--those requiring no input or action by the vehicle occupant--can operate independently in an active manner; an airbag is one such device . Vehicle safety professionals are generally careful in their use of language to avoid this sort of confusion, though advertising principles sometimes prevent such semantic caution in the consumer marketing of safety features . Further confusing the terminology, the aviation safety community uses the terms "active" and "passive" in the opposite sense from the automotive industry . </P> <P> In patent applications, various airbag manufacturers sometimes use the catchall term' inflatable occupant restraint systems' for vehicle airbags . </P> <P> The airbag specified for automobile use traces its origins to air - filled bladders as early as 1951 . </P> <P> The invention is credited independently to the American John W. Hetrick who in 1951 registered for the first airbag patent that was granted #2,649,311 by the United States Patent Office on 18 August 1953 . German engineer Walter Linderer who filed German patent #896,312 on 6 October 1951 was issued on 12 November 1953, approximately three months after American John Hetrick . Hetrick and Linderer's airbags were both based on a compressed air system, either released by spring, bumper contact or by the driver . Later research during the 1960s showed that compressed air could not inflate the mechanically based airbags fast enough for maximum safety, leading to the current chemical and electrically based airbags . </P>

When was the first airbag installed in a car