Journal reference: Annals of Internal Medicine
Forcing older drivers to do mandatory cognitive tests slashes the rate of vehicle collisions among older adults by one in ten, a study suggests.
Researchers in Japan studied the impact of a pensioners rule imposed in 2017 that required all people over 75 years old to do a cognitive test every five years in order to keep their license.
Within two years, the country saw a drop in car accidents among older adults by almost 4,000. But at the same time, injuries among over-75s on bicycles and sidewalks rose.
Cognition slows as we age, slowing reaction times to events on the road such as someone running in front of a car or a vehicle applying an emergency brake, raising the risk of collisions among elderly drivers.
Cognitive tests for drivers over 75 years old in Japan have led to a fall in car crashes, data shows (stock image)
Elderly adults in the US and UK account for a slightly higher proportion of accidents than others by age group, campaigners say.
In Japan, people over 75 years old have been required to take cognitive tests when they renew their license since 2017.
This involves testing a driver’s memory — by getting them to recall illustrations without being offered prompts — and perception of time — by being asked the year, month, date, day of the week and current time.
Results are given as either ‘have risk of dementia’ or ‘have no risk of dementia’.
Japan requires over-75s to renew their driving licenses every five years, in line with the amount of time between renewals for all adults.
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In the US, laws vary widely by state — but most require senior drivers to take a vision test when getting their licenses renewed. In the UK, drivers over 70 years old must renew their license every three years — rather than the standard 10.
In the latest study, scientists at the Johns Hopkins School of Public Health in Maryland analyzed 602,885 police reports of collisions among drivers over 70 years old.
Researchers looked at reports from 2012 to 2017 — before the new restriction came in — and until December 2019 — covering the two years after.
Results showed there were 3,670 fewer collisions among drivers over 75 years old on average over the period after the tests were brought in.
Calculated as a rate among older people, this was a drop from 347 accidents a year per 100,000 person-years to 299 per 100,000 — or down 14 percent.
The drop was mostly among men, with rates falling from 619 to 506 — down 18 percent. But women also saw a drop from 157 to 151 — down four percent.
Data for 2019 showed there were 41 fatal collisions in Japan due to someone mistakenly pressing the accelerator instead of the brake. Of these, 28 (68 percent) were caused by drivers over 75 years old.
During the study, the scientists also looked at the number of injuries among pedestrians and cyclists over 75 years old.
It was not clear whether these injuries were due to older people, or because other drivers struck them.
Of the 196,889 reports of injuries analyzed, results showed that after the rule change came in, these rose by 959 on average. This mainly was among women (805 more injuries).
The researchers suggested that the policy had led to fewer collisions because it had led to more people giving up their licenses.
Led by Dr Haruhiko Inada, a post-doctoral fellow at Johns Hopkins University, they said: ‘Since around 2017, the number of older drivers who voluntarily surrendered their licenses has sharply increased for unclear reasons, especially in the oldest age groups, which might have contributed to crash reduction.
‘Cognitively screening older drivers at license renewal and promoting voluntary surrender of licenses may prevent motor vehicle collisions.’
They suggested men were more likely to cause car collisions than women because men are more likely to hold driving licenses when they’re older.
Dr Inada added: ‘Safety measures need to be strengthened for older cyclists and pedestrians.
‘We should also provide older people with necessary care to prepare for driving cessation and safe, alternative transport means.’
Japan has one of the fastest ageing societies in the world – with one in five citizens aged 70 or older.
It is also a nation of drivers and car lovers, with nearly 80 million vehicles on the road. Keeping traffic accidents down as people get older is a growing problem.
The study was published in the Journal of the American Geriatrics Society.