Sam Peltzman Thinks You Should Belt Up

What does economics have to do with seat belts?

You’re referring to my 1975 paper, which argued that because seat belts reduce the likelihood that drivers are harmed if they crash, they encourage more reckless driving.

So do seat belts lead to more accidents?

I asked my research assistant at the time to statistically estimate the counterfactual scenario—what the death rate would be in the absence of seat belts—so we could compare it to the actual death rate and find the benefit of the regulation. He couldn’t find any benefit. Upon further investigation we found that the regulation had provoked an offsetting behavioral response. When we held other factors constant, the 1966 regulations [the first set of US auto safety regulations, which required that all vehicles be fitted with seat belts and other safety devices] caused more accidents; but the accidents tended to be less harmful, so the net number of driver fatalities was unaffected.

Subsequently, scholars have questioned your findings. Do you stand by the results?

If an undergraduate handed in the seat-belt research nowadays as a term paper, I would ask her to redo it. It was a primitive piece of work; but it came up with a provocative answer to a well-posed question. My critics don’t quarrel with the basic theory of an offsetting response. There is a continuing debate about the magnitude of this response in specific cases.

Should we scrap seat belts?

I never say you shouldn’t wear a seat belt. People have taken me to be anti–seat belt. That’s ridiculous. It’s a complete misunderstanding of what I was trying to do. Regulation in its essence tells you and me that we can’t do what we otherwise would want to do; but it doesn’t take the basic incentive away. So you have to understand that one effect of any regulation is going to be offsetting behavior of some kind.