Restricted licensing among older drivers in Iowa

Braitman, Keli A. / Chaudhary, Neil K. / McCartt, Anne T.
Journal of Safety Research
December 2010

Objectives: To determine whether Iowa's license restriction program identifies older drivers who appear to be at greater crash risk and to assess compliance with license restrictions.
Methods: A total of 522 drivers 70 and older who were attempting to renew their driver's licenses at licensing offices in Iowa participated in two telephone surveys: one shortly after renewal to discuss driving before renewal and another 6months later to assess any changes. Surveys assessed driving behavior, crashes, and violations as well as self-reported visual impairments, prescription medications, and physical mobility limitations.
Results: Of the 522 drivers, 232 renewed their licenses without having to take a road test (Group 1), and 290 were required to take a road test; of the drivers taking a road test, 191 renewed without restrictions (Group 2), 93 received restrictions (Group 3), and 6 had their licenses suspended (Group 4). The small number of drivers with suspensions precluded including this group in analyses. There were clear distinctions among drivers in the first three groups at the initial survey. Driver age increased across Groups 1-3, as did some visual impairments, number of prescription medications, and physical mobility limitations. Many drivers who received restrictions (Group 3) already were driving fewer miles than drivers in Groups 1-2, and were driving less often at night and on high-speed roads. Following license renewal, reported average weekly mileage decreased more among drivers with license restrictions (Group 3) (36%) than among drivers without restrictions (Groups 1-2) (4% each). For all license restriction types (headlight, geographic area, or speed), decreases in the likelihood of driving during these restricted conditions were greater for drivers with the relevant restrictions than without. Most drivers complied with restrictions.
Conclusions: Iowa's license restriction program identifies drivers with more self-reported visual impairments, prescription medications, and physical mobility limitations. Driving exposure was reduced among drivers who received restrictions, though it appears in some cases the restrictions reinforced decisions already made by drivers.
Impact on industry: License restrictions may be an effective alternative to premature driving cessation and provide some drivers additional time on the road and hence continued mobility and independence. However, overall safety benefits of license restrictions are yet unknown.

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