The impact of a vision screening law on older driver fatality rates.

Abstract

To evaluate the impact of the Florida visual acuity licensing standard for drivers 80 years and older on fatal motor vehicle collision (MVC) involvement. Motor vehicle collision fatality rates for all Florida residents and for drivers 80 years and older were compared before and after the visual acuity licensing standard was implemented in January 2004. From 2001 to 2006, there was a nonsignificant (P = .06) increase in MVC fatality rates in Florida; in contrast, fatality rates among drivers 80 years and older demonstrated a significant downward linear trend (P = .01). When comparing prelaw (2001-2003) and postlaw (2004-2006) periods, the fatality rate among all-aged occupants increased by 6% (rate ratio, 1.06; 95% confidence interval, 0.99-1.14); conversely, fatalities among drivers 80 years and older decreased significantly by 17% (rate ratio, 0.83; 95% confidence interval, 0.72-0.98). Despite little evidence for an association between visual acuity and MVC involvement, the results of this study suggest that a vision screening law targeting Floridians 80 years and older resulted in a reduction in the MVC fatality rate among such drivers. The exact mechanism responsible for this association is unclear and future research should attempt to identify what might explain this relationship.