Injury risk as a function of age of vehicles and injury reduction in 1967, 1968 and 1969, model cars.

It is shown that in the U.S.A. injury risk is a function of the age of cars (or other related factors), independent of model year before 1967, and that 1968 and 1969 model cars have at least a 15 percent, possibly a 25 percent, reduced injury risk for the 1967 model year. North Carolina data suggests a reduction in injury risk by about 10 percent.