by 45-80%" and "significantly reduced traffic fatalities and serious injuries resulting from fatal crashes by 8 and 9%, respectively." The authors note that these "results suggest that if all states had primary enforcement seatbelt laws then regular youth seatbelt use would be nearly universal and youth fatalities would fall by about 120 per year." Regulations Unece has some regulations on seat belt. Opposition A number of groups and individuals are opposed to seat belt legislation. The most common grounds for opposition are: The view that laws requiring the wearing of seat belts are an infringement of individual liberty. Claims that official estimates of the number of lives saved by seat belts are overstated or fail to take into account additional risks for other road users. Risk compensation and other theories The most common basis for disputing estimates of the benefits of seat belts is risk compensation and risk homeostasis, advanced by researchers John Adams and Gerald Wilde. The idea of this theory is that, if the risk of death or injury from a car crash is reduced by the wearing of seat belts, drivers will respond by reducing the precautions they take against crashes. Adams accepts the hypothesis that wearing seat belts improves a vehicle occupant's chances of surviving a crash. In order to explain the disparity between the agreed improvement in crash survival and the observed results, Adams and Wilde argue that protecting someone from the consequences of risky behaviour may tend to encourage greater risk taking. Wilde states, "to compel a person to use protection from the consequences of hazardous driving, as seat belt laws do, is to encourage hazardous driving. A fine for non-compliance will encourage seat belt use, but the fact that the law fails to increase people's desire to be safe encourages compensatory behaviour." Studies and experiments have been carried out to examine the risk compensation theory. In one experiment subjects were asked to drive go-karts around a track under various conditions. It was found that subjects who started driving belted did not drive any slower when subsequently unbelted, but those who started driving unbelted did drive consistently faster when subsequently belted. A study of habitual non-seat belt wearers driving in freeway conditions found evidence that they had adapted to seat belt use by adopting higher driving speeds and closer following distances. In another study, taxi drivers who were habitual non-wearers were timed over a