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
Acts of the claimant has been overtaken by statute. In "Froom v Butcher" (1976) QB 286 Denning MR assessed the percentage contribution made by a claimant who failed to wear a seat belt (at p295): The wearing of seat belts then became compulsory (see the Wearing of Seat Belts Regulations 1983 and the Motor Vehicles (Wearing of Seat Belts in Rear Seat by Adults) Regulations 1991). The current thinking would not support limiting damages by a figure of 25% and if, for example, the claimant was thrown out of the vehicle because no seat belt was worn, a substantial finding of contributory negligence should