It is undeniable that physical and cognitive degeneration at older ages compromises driving ability. Research conducted by myself and Seth Seabury of the RAND Corporation, however, indicates that drivers 65 and older are only 16 percent more likely per mile driven to cause a traffic accident than are drivers ages 25–64. And their total contribution to the nation's traffic accidents is surprisingly small.
Older drivers account for about 15 percent of licensed drivers, but cause only 7 percent of all traffic accidents. Contrast this with drivers ages 15–24 who account for 13 percent of licensed drivers, but cause 43 percent of all traffic accidents.
One reason why: older drivers adjust their driving behavior as they age, avoiding driving at night, avoiding high speed zones, and driving far fewer miles. Most older individuals eventually stop driving of their own accord.
Many stop driving in part because they fear they might injure someone else. But the reality is that older drivers themselves are almost six times more likely to be injured in an automobile accident than are drivers ages 25-64. Thus, older drivers face a much greater risk of being harmed from the actions of younger drivers than the other way around.
I have little doubt that more intensive screening would identify some older drivers whose licenses should be restricted or revoked entirely. But the cost would be high, and we have no evidence such screening would be any likelier to identify particularly risky older drivers than it would be to identify particularly risky middle-aged or younger drivers. At the same time, screening would likely result in the premature termination of driving for some.
There is more we can do through public policy to improve the safety of automobile travel for older drivers. Promoting technological innovations, such as autonomous vehicles, that promise to reduce accident rates overall while simultaneously providing older individuals who can no longer drive safely an alternative means of transportation, is likely to have the single greatest impact on the safety and well-being of older drivers and passengers.
David S. Loughran is a senior economist at RAND and professor of economics at the Pardee RAND Graduate School.
This commentary appeared in The New York Times on October 20, 2010