Objective: To assess the relationship between state driver's license renewal policies and fatal crashes involving drivers aged 70 years or older (seniors).
Design and analysis: Poisson regression methods were used to isolate the relationship between different state policies mandating vision tests, knowledge tests, or road tests for driver's license renewal and fatal crashes involving senior drivers. The analysis controlled for differences among states, other than their renewal policies, likely to influence senior motor vehicle crashes.
Setting: United States, 1985 through 1989.
Participants: All fatal crashes identified in the National Highway Traffic Safety Administration Fatal Accident Reporting System involving at least one driver aged 70 years or older.
Main outcome measure: The number of fatal crashes per state in which at least one of the drivers was aged 70 years or older. When a single fatal crash involved more than one senior driver, each was included.
Results: State-mandated tests of visual acuity, adjusted for license renewal period, were associated with lower fatal crash risk for senior drivers (relative risk, 0.93; 95% confidence interval, 0.89 to 0.97). Knowledge tests, when added to vision tests and applied only to seniors, provided a nonsignificant reduction in the senior fatal crash risk (relative risk, 0.91; 95% confidence interval, 0.79 to 1.05).
Conclusion: Tests of vision and knowledge for senior drivers at license renewal merit further attention as a means of improving senior traffic safety.