To make sure a seatbelt restrains an occupant as early as possible in a crash, thereby reduce the load on the occupant in a violent crash, Autoliv has developed pretensioners.These tighten the belt during the very first fractions of a second in a crash. Pretensioners also reduce the risk of "submarining" (the car occupant slip under a loosely tightened seatbelt). Autoliv´s pretensioners use pyrotechnic devices that are typically controlled by the same sensor system as the airbags.

Pretensioner devices can be added to any of the belt anchorage points, however, lap pretensioners are normally used in combination with retractor or buckle pretensioners. All systems can be tuned to maximize the protection for the occupant.

Click here to see the movie that illustrates the pretensioner.