Previous research has shown that older drivers pose less risk to other people outside of their vehicles than young drivers do; however, risk of crash involvement increases somewhat after approximately age 70—75, and risk of injury or death in the event of a crash increases sharply beyond this age range. Several states attempt to address these risks through laws and policies related to driver license renewal; however, there is little evidence regarding the effectiveness of such policies. Data from 46 U.S. states from years 1985-2011 were examined. Laws and policies investigated were: frequency of license renewal; requirements for drivers to renew their license in person; requirements to pass a vision test, knowledge test, and on-road driving test; and requirements for physicians to report drivers due to specific medical diagnoses and/or concerns about driving ability. Population-averaged negative binomial regression was used to estimate the impact of licensing policies on population-based fatal crash involvement rates of older drivers while adjusting for the effects of other factors that might influence rates of fatal crashes. Requiring license renewal to be conducted in-person was associated with a 9 percent reduction (95% Confidence Interval [CI]: 2% — 14%) in fatal crash involvement rates for drivers ages 55 and older. The reduction appeared to be largest for drivers ages 85 and older (25%, 95% CI: 11% — 37%); however, evidence that the effect varied by age was not statistically significant. Fatal crash involvement rates of drivers ages 85 and older were significantly lower in states that required drivers to pass a vision test when renewing their license than in states that did not; however, changes in vision testing requirements were not associated with changes in rates of fatal crashes, suggesting that the cross-sectional differences between rates of fatal crashes in states with versus without vision testing requirements may be confounded by other factors. Increasing the frequency of license renewals, requiring drivers to pass a knowledge test or an on-road driving test, and requiring physicians to report patients to the licensing authority were not associated with statistically significant reductions in fatal crash involvement rates. Mandatory in-person license renewal was associated with significant reductions in population-based fatal crash involvement rates for older drivers; the largest effects were observed for the oldest drivers. Determining whether this is primarily due to removing unsafe older drivers from the driving population or due to possibly-premature driving cessation is beyond the scope of this study and should be investigated in future studies. Other driver license renewal policies investigated were not found to reduce fatal crash involvement rates of older drivers. (Author/publisher)
Samenvatting