Keeping Seniors Safe and Mobile – An Evaluation of a Local Drive Test Option

Abstract

This study builds on an earlier AAAFTS-sponsored project to develop a database of state driver licensing policies and practices pertaining to older and/or medically-at-risk drivers. As part of the earlier project, information was gathered on 40 “noteworthy initiatives” being undertaken by the states. The current study evaluated the safety and mobility consequences of one of these initiatives: the offering of local drive tests. Local drive tests (LDTs) are an alternative to standard road tests typically offered by state driver licensing agencies. LDTs allow some drivers who otherwise might not qualify to renew their licenses the option of taking a road test near their homes, on familiar roadways, and/or to specific destinations they want or need to access. Drivers who pass this more limited road test are then restricted to driving only within the specific area or radius where they were tested, and often have additional restrictions placed on their licenses.

This study evaluated LDTs using data provided by the Iowa Office of Driver Services. ODS staff identified 239 drivers who took LDTs between January 2005 and August 2008 inclusive. Of these, 236 were age 65 or older and 205 went on to hold an LDT license. The median age for these 205 case drivers was 85, and almost two-thirds were female. Although 43% of the LDT license recipients lived in rural areas or small towns with populations less than 2,500, this was not dissimilar from the overall population of Iowa residents. In addition to their area restrictions (most often either 5 or 10 miles of their homes, or within the city limits of their communities), 44% of LDT license recipients were also restricted to no nighttime driving, 35% to operating their vehicle below a certain speed (or only on roadways with speed limits not exceeding a certain level), and 15% to no Interstate or freeway driving. The average period of time the 205 LDT drivers held their licenses was 2.3 years; however, this number does not take into account some drivers who held LDT licenses prior to the January 2005 beginning of the study, and others who were still holding a valid LDT license at the end of the study period.

Each case driver’s period of driving exposure was determined based on the issue date for their LDT license (start date for exposure) and the date of license expiration, surrender, suspension or cancellation, or the death of the driver (end date of exposure). Drivers who were alive and still held a valid license at the end of the study period were assigned an exposure end date of December 31, 2010, allowing for at least two full years of follow-up for each LDT driver. A 4:1 control sample of non-LDT drivers was identified matched on age (plus or minus one year), gender, and residential city/town population (5 categories). Control drivers were also required to possess a valid driver’s license during their corresponding case driver’s period of exposure.

Eleven case drivers were involved in 13 crashes during the study period, and were judged to be either solely (10) or jointly (1) at fault in 11 of these crashes. This translates to an overall annual crash involvement rate of 0.0284, and an at-fault annual crash involvement rate of 0.0240. Corresponding rates for the control drivers were 0.0196 (all crashes) and 0.0087 (at-fault crashes). Risk ratios and 95% confidence intervals comparing the two were 1.44 (0.77-2.72) for total crashes, and 2.75 (1.28-5.93) for at-fault crashes. Similarly, the relative risk of conviction for a moving violation for LDT vs. non-LDT drivers was 0.55 (0.16 – 1.82). Although these results show LDT drivers to have a modestly elevated risk of at fault crash involvement, their overall crash rate of 0.0284 is only slightly higher than that for all Iowa drivers ages 65+, and lower than that for other groups of drivers, including younger drivers and males. Taken together, findings from this study suggest that local drive test licenses, at least as offered in Iowa, are a viable option for extending mobility to some older drivers, without posing undue safety risks to either the drivers themselves or to others sharing the roadway.