Seat belt that required a particular technical approach would rapidly become dated as motor manufacturers would tool up for a particular standard which could not easily be changed. For example, in 1969 there were competing designs for lap and three-point seat belts, rapidly tilting seats, and airbags being developed. But as countries started to mandate seat belt restraints the global auto industry invested in the tooling and standardized exclusively on seat belts, and ignored other restraint designs such as air bags for several decades As of 2016, seat belt laws can be divided into two categories: primary and secondary. A primary seat
Seat belt with this door-mounted system. General Motors began offering automatic seat belts on the Chevrolet Chevette. However, the company reported disappointing sales because of this feature. A study released in 1978 by the United States Department of Transportation claimed that cars with automatic seat belts had a fatality rate of .78 per 100 million miles, compared with 2.34 for cars with regular, manual belts. In 1981, Drew Lewis, the first Transportation Secretary of the Reagan Administration, influenced by studies done by the auto industry, dropped the mandate; the decision was overruled in a federal appeals court the following year, and then