Testing Peltzman's Theory of Driver Intensity

The 1966 National Traffic and Motor Vehicle Safety Act empowers the federal government to set motor vehicle safety performance standards. By passing the Act, Congress intended to lower the motor vehicle crash and death rates. Sam Peltzman has since challenged the assumption that safer cars lead to fewer crash‐related deaths. His theory is that safer cars instill a feeling of protection in motorists that encourages them to drive more recklessly than in unsafe cars. Peltzman has devised a regression equation that predicts what the motor vehicle death rate would be without auto safety regulation. According to it, the total motor vehicle death rate without regulation is not much different from what we have experienced with regulation. Thus Peltzman concludes the auto safety regulation was ineffective. But Peltzman's equation should not be looked upon as absolute. Other predictive equations of statistical quality equal to Peltzman's model contradict its findings. A series of regressions constructed solely on the basis of maximizing statistical quality with no underlying theory consistently predicts a higher motor vehicle death rate without auto safety regulation than with it. Thus Peltzman's theory lacks the statistical foundation he claims for it.