Seat belts save lives. At least conventional wisdom says so. But is this really the case?
Seat belts are useful because the reduce the chance that–given that you are in an accident–you will die or sustain a serious injury. But wearing a seat belt may give drivers an incentive to drive more recklessly since the driver may believe that accidents are not as dangerous. Thus, seat belts may increase accidents but reduce injuries when people are in accidents. The net benefit may be ambiguous.
An Economist magazine article (“A hazardous comparison“) expands on this and other safety issues.
In one experiment, a British psychologist, Ian Walker of Bath University, simply got on his bicycle and monitored the behaviour of 2,300 vehicles that overtook him. When he wore a helmet, drivers were much more likely to zoom past him with little room to spare; when he was bare-headed (and indeed when he wore a female wig) the amount of space that motorists left would increase. An experiment in Munich found that the drivers of taxicabs fitted with anti-lock braking systems were involved in no fewer accidents than those without. That is because the former used those superior brakes not to practise prudence but to drive more aggressively.
Such unintended effects are not confined to Europe. John Adams, a transport expert at University College London, has compiled data from all over the world to show that laws making drivers wear seatbelts do not make roads safer; they move deaths from inside cars to outside them because they encourage bad driving. The number of young children killed on the roads has fallen in recent years, he notes—but mainly because they are rarely allowed out alone, so today’s teenagers have less skill at navigating hazardous roads; and as a result, the number of teenagers killed in car accidents has jumped. He lauds the Dutch experiment in “naked streets” where most road signs and markings were removed to force travellers to keep their wits about them.