Consuming Risk Reduction

I had the opportunity to ski in Colorado over the holiday season (the picture is not of me nor a reflection on my skill level!). One of the things that is clearly noticeable on the slopes and lift lines is the number of people that wear ski helmets. I would estimate that 75% of participants in every demographic group wear a helmet. This is vastly different from the first time I skied in the early 1970's. Helmets are available as rentals and come in many different colors and styles from numerous manufacturers. Clearly safety concerns have fueled the demand, acceptance, and use by the general public. The key question - have helmets reduced the number of head injuries over the last 40 years or have people just consumed their risk reduction by taking greater risks on the slopes? Have the use of helmets increased risk taking that has led to other types of injuries - such as broken legs?

Consider, for example, the results of a famous experiment conducted in the early 1990's in Germany. Part of a fleet of taxicabs in Munich was equipped with anitlock brake systems (ABS), technological innovation that vastly improves braking, particularly on slippery surfaces. The rest of the fleet was left alone, and the two groups - which were otherwise perfectly matched - were placed under careful and secret observation for three years. You would expect the better brakes to make for safer driving. But that is exactly the opposite of what happened. Giving some drivers ABS made no difference at all in their accident rate; in fact, it turned them into markedly inferior drivers. They drove faster. They made sharper turns. They showed poorer lane discipline. They braked harder. They were more likely to tailgate. They didn't merge as well, and they were involved in more near misses. In other words, the ABS systems were not used to reduce accidents; instead, the drivers used the additional element of safety to enable them to drive faster and more recklessly without increasing their risk of getting into an accident. As economists would say, they consumed the risk reduction, they didn't save it.