While still the top killer of Americans aged 5 to 34, traffic accidents have been steadily declining for the last several decades. Even as vehicle miles driven per capita has steadily increased, regular advances in technology, new government policies, and changes in driving behavior brought on by cultural forces have been able to significantly reduce the rate of auto fatalities since the peak of the late 1960s and early 1970s.
Fairfield charts this progress by plotting miles traveled against deaths per 100,000 population and finds "a pattern that looks like a plateau followed by a steep drop. It evokes the theory of punctuated equilibrium, proposed by the paleontologists Stephen Jay Gould and Niles Eldredge, which suggests that instead of continuous gradual evolution, change occurs abruptly after periods of virtual standstill."
"You see fatalities drop after a breakthrough in new technologies or behaviors, and then plateau until the next one," said David L. Strickland, administrator of the National Highway Traffic Safety Administration. "It takes time for new safety technologies to work their way into the whole fleet of cars on the road."