The Gerontologist Advance Access first published online on June 2, 2009
This version published online on June 17, 2009
The Gerontologist, doi:10.1093/geront/gnp039
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Do Restricted Driver's Licenses Lower Crash Risk Among Older Drivers? A Survival Analysis of Insurance Data From British Columbia
2 Performance Analysis Services, Insurance Corporation of British Columbia, North Vancouver, Canada
3 Department of Gerontology, Simon Fraser University at Harbour Centre, Vancouver, British Columbia, Canada
1 Address correspondence to Glenyth C. Nasvadi, MA, Performance Analysis Services, Insurance Corporation of British Columbia, 404-132 West Esplanade, North Vancouver, BC, Canada V7M 1A2. E-mail: glenyth.nasvadi{at}icbc.com
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Abstract |
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Purpose: Faced with an aging driving population, interest is increasing in the use of restricted licenses or "graduated delicensing" for older drivers to allow them to safely retain a driver's license. The primary purpose of this study was to determine whether restricted licenses are successful at mitigating number of crashes per year and whether they can extend the period of crash-free driving for aging adults. Design and Methods: Using a cohort study design, licensing and insurance claims crash records of all drivers aged 66 years and older in British Columbia were examined for the years 1999–2006. Nonparametric and Cox proportional hazards survival analyses were used to compare restricted vs. unrestricted drivers and to estimate crash risks. Results: The risk of causing a crash was 87% lower for restricted drivers compared with unrestricted drivers after controlling for age and gender. The most common restriction was a combination of daylight driving only plus a speed maximum of 80 km/hr. Restricted drivers retained a driver's license for a longer period of time than unrestricted drivers and continued to drive crash free longer than unrestricted drivers. There was no difference in severity of collisions, and results suggest a high level of compliance with daylight-only restrictions. Implications: These findings suggest that driving restrictions may be effective for prolonging the crash-free driving of some aging drivers, thus supporting their continued independence and delaying institutionalization. Further studies are needed to determine which drivers are most likely to benefit from restricted licenses.
Keywords: Graduated delicensing, Conditional license, Driving cessation, Prolong driving, Driving environment
Received April 14, 2008; Accepted June 19, 2008
Decision Editor: William J. McAuley, PhD