Today, all cars have seat belts, but that was not true 50 years ago. In the 1960s, Ralph Nader's book Unsafe at Any Speed generated much public concern over auto safety. Congress responded with laws requiring seat belts as standard equipment on new cars. How does a seat belt law affect auto safety? The direct effect is obvious: When a person wears a seat belt, the probability of surviving an auto accident rises. But that's not the end of the story because the law also affects behavior by altering incentives. The relevant behavior here is the speed and care with which drivers operate their cars. Driving slowly and carefully is costly because it uses the driver's time and energy. When deciding how safely to drive, rational people compare, perhaps unconsciously, the marginal benefit from safer driving to the marginal cost. As a result, they drive more slowly and carefully when the benefit of increased safety is high. For example, when road conditions are icy, people drive more attentively and at lower speeds than they do when road conditions are clear. Consider how a seat belt law alters a driver's cost - benefit calculation. Seat belts make accidents less costly because they reduce the likelihood of injury or death. In other words, seat belts reduce the benefits of slow and careful driving. People respond to seat belts as they would as they would to an improvement in road conditions - by driving faster and less carefully. The result of a seat belt law, therefore, is a larger number of accidents. This sounds like a made - up story but there is actually a famous paper on this: 'The Effects of Automobile Safety Regulation,' from 1975 by Sam Peltzman. He argued that because seat belts reduce the likelihood that drivers are harmed if they crash, they encourage more reckless driving. His empirical findings suggest that seatbelt laws did not affect highway death rates. This is called the 'Peltzman effect': people are less careful and they exert less caution when they are/feel protected against bad outcomes. Another example of the Peltzman effect: Sweden switched from driving on the left to driving on the right, overnight, in 1967 . Everyone expected a huge increase in traffic accidents, but instead accidents went down because drivers were paying more attention. This long paragraph is most closely related to which of the ideas/principles listed below?