Effect of a cognitive test at license renewal for older drivers on their crash risk in Japan

Abstract

ObjectiveTo evaluate the effect of adding a cognitive test to a license renewal procedure for drivers aged 75 years or older in reducing their motor vehicle collisions (MVCs). The test has been obligatory since June 2009.MethodsUsing monthly police-reported national data on MVCs from January 2005 through December 2016, we calculated the rates of MVCs per licensed driver-year by sex and age group (70–74, 75–79, 80–84 and 85 years or older) for each month together with the ratios of MVC rates of drivers in the three oldest age groups (which are subject to the test) to those of the 70–74 years group (not subject to the test) to control for extraneous factors affecting MVCs over the study period. Then, we conducted an interrupted time-series analysis by regressing the rate ratio stratified by sex and age group on the number of months from January 2005, June 2009 (when the cognitive test was introduced to a license renewal procedure) and June 2012 (when all drivers subject to the test have taken it at least once).ResultsThe rates showed a longitudinal decrease in male and female drivers over the study period without any apparent effects of the introduction of the cognitive test while no significant decrease was observed in the rate ratios after the introduction of the cognitive test.ConclusionsThere were no clear safety benefits of the cognitive test for drivers aged 75 years or older to reduce their MVCs.

Regional Gray Matter Volume Identifies High Risk of Unsafe Driving in Healthy Older People

“…In developed countries, the number of traffic accidents caused by older drivers is increasing over time, along with the aging population. In Japan, the number of licensed drivers aged over 65 years has increased in recent years, exceeding 18 million in 2018, and the number of fatal accidents caused by older drivers has maintained an upward trend (Ichikawa et al, 2020). Although previous studies consistently showed that individuals with dementia are at increased risk of unsafe driving among the older population (Drachman and Swearer, 1993;Frittelli et al, 2009), surprisingly, a report published by the National Police Agency revealed that approximately half of the older drivers who caused fatal accidents were cognitively normal (National Police Agency, 2020).…”

Age-based medical screening of drivers in Switzerland: an ecological study comparing accident rates with Austria and Germany

“…of a benefit of mandatory age-based screening policies on the safety of elderly drivers could be demonstrated [2][3][4][5][6][7].…”

“…Other studies, however, have observed negative effects: one study found higher fatality rates among pedestrians and cyclists in Finland (with agebased screening policy) compared with Sweden (no such policy) [10]. Two studies found higher injury and mortality rates of pedestrians and cyclists, respectively, after a cognitive test was added to the existing licensing renewal procedure [6,9]. It is hypothesised that elderly persons who have had their driver's licence revoked or voluntarily handed it in due to the screening procedure may switch to the unprotected modes of transport, which are significantly less safe for them [2,8].…”

“…The use of per-distance accident rates of car drivers is an improvement over previous studies, in which rates were usually calculated in relation to population size or to the number of driver's licence holders (e.g. [6,29,30]). Using distance-related rates made it possible to take into account differences in driving performance between the countries.…”

“…Most reviews and individual studies looking into the effects of age-based screening procedures have failed to provide clear evidence of a benefit for the safety of elderly drivers [e.g., [2][3][4][5][6][7]. On the contrary, there are some studies that found negative safety effects for elderly road users [8][9][10].…”