Seat Belts & Parts

A seat belt, sometimes called a safety belt, is a harness designed to hold the occupant of a car or other vehicle in place if a collision occurs. more...

Seat belts are intended to reduce injuries by stopping the wearer from hitting hard interior elements of the vehicle or from being thrown from the vehicle. In cars seat belts also prevent rear-seat passengers from crashing into those in the front seats.

Types of seat belts

Lap: Adjustable strap that goes over the waist. Used frequently in older cars, now uncommon except in some rear middle seats (also in passenger aircraft).

Automatic: Any seatbelt that closes itself automatically. Used mainly in older luxury models.

Sash: Adjustable strap that goes over the shoulder. Used mainly in the 1960's, but of limited benefit because it is very easy to slip out of in a collision.

Lap and Sash: Combination of the two above (two separate belts). Mainly used in the 1960s and 1970s, usually in the rear. Generally superseded by three-point design.

Three-point: Similar to the lap and sash, but one single continuous length of webbing. Both three-point and lap-and-sash belts help spread out the energy of the moving body in a collision over the chest, pelvis, and shoulders. Until the 1970's three-point belts were commonly available only in the front seats of cars, the back seats having only lap belts. Evidence of the potential for lap belts to cause separation of the lumbar vertebrae and the sometimes associated paralysis, or "seat belt syndrome", has led to a revision of safety regulations in nearly all of the developed world requiring that all seats in a vehicle be equipped with three-point belts.

Five-point harnesses are safer but more restrictive seat belts. They are typically found in child safety seats and in racing cars. The lap portion is connected to a belt between the legs and there are two shoulder belts, making a total of five points of attachment to the seat.

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