"A 2-Minute Test Can Identify the Crash Risk of Older Drivers"

[Sportschosun, Reporter Jang Jong-ho] A way has been found to identify older drivers who face a high risk of traffic accidents, even if they have no history of traffic violations or crashes.

According to the traffic accident analysis system of KoROAD, traffic accidents caused by drivers aged 65 and older rose sharply from 31,072 cases in 2020 to 42,369 in 2024. In particular, crashes involving older drivers have a higher fatality rate than those in other age groups. That makes it even more important to identify high-risk drivers, but an effective method has still been lacking.

Researchers have long tried to predict crash risk using various cognitive tests, but studies have reached mixed conclusions about whether test results actually translate into real-world accidents. Safe driving depends not only on cognitive function, but also on a driver's ability to recognize and adjust to changes in their own driving skills as they age.

To examine this issue, a research team led by professors Kim Ki-woong and Ji Won Han from the Department of Psychiatry at Seoul National University Bundang Hospital studied whether older drivers can accurately assess their own driving risk and how much risk may go undetected by that approach.

The team analyzed the driving-risk questionnaire results of 1,673 male drivers aged 60 and older who participated in the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD), and compared them with National Police Agency traffic accident records from the following two years. From the 13-item driving-risk questionnaire, they used questions about the number of traffic violations, crashes, and at-fault crashes over the past three years. The survey was given both to the drivers themselves and to family members such as spouses and children, allowing the two sets of responses to be compared.

The analysis found that during the two-year follow-up period, 290 of the 1,673 participants, or 17.3%, were confirmed to have caused at-fault traffic accidents involving injuries. Drivers who reported more traffic violations and crash experiences on the questionnaire were also more likely to cause a later accident, with the risk rising 1.28-fold for each additional point. In other words, older drivers' own reports of violations and crash history could actually predict future accidents.

What stood out was that 111 of the 290 drivers who caused accidents, or 38.3%, had said at the time of the survey that they had no traffic violations or crash experience. In other words, they belonged to a "silent risk group" that the questionnaire could not detect. Even their closest family members failed to notice the warning signs in advance. While 94.3% of all participating family members said they had never seen any traffic violations or crashes, most families of the 111 silent-risk drivers gave the same answer, meaning family responses also could not identify them beforehand.

So, is there a way to identify this "silent risk group" in advance? The research team conducted an additional analysis of 876 people who said on the questionnaire that they had no history of violations or crashes. When age, years of education, and cognitive test results were analyzed together, shorter education and longer completion times on the Trail Making Test were associated with a higher crash risk. The Trail Making Test is a type of cognitive assessment that measures the ability to shift attention and make quick judgments while alternately connecting numbers and letters.

Specifically, drivers with nine years of education or less, equivalent to middle school graduation or below, and a Trail Making Test completion time of 180 seconds or more had a crash rate of 20.9%, more than twice as high as drivers who met neither condition, at 9.1%. The difference remained even after adjusting for other factors such as age. The team explained that shorter education may reflect a reduced ability to notice and judge one's own functional decline, while longer test times may indicate slower processing and weaker executive function in complex driving situations.

The researchers added, however, that this standard is not meant to restrict driving. Rather, it is intended to identify people who need a more detailed driving assessment first. They also noted that years of education were used not as a measure of academic achievement, but as an indicator of how well a person may be able to detect changes in their own function.

Corresponding author Professor Kim Ki-woong said, "A significant number of the drivers who caused accidents were part of a silent risk group that neither they nor their families recognized," and added, "The results show that we should not assume someone is safe simply because they have no record of traffic violations or crashes, and that a separate method is needed to identify these high-risk drivers."

He emphasized, "The purpose of this study is not to restrict all older drivers, but to accurately identify the small number at high risk and protect the mobility rights of the majority who drive safely."

First author Professor Ji Won Han said, "If we can first identify high-risk individuals in clinics and at driver's license renewal sites using only a simple check that takes about two minutes, such as years of education and the Trail Making Test, it could help connect them to a more detailed driving evaluation." She added, "We plan to continue follow-up studies by expanding the research to female drivers and a wider range of driving environments so that the findings can be used to prevent accidents among older drivers."

Meanwhile, the study was published in the Journal of the American Geriatrics Society (JAGS), an international journal in the field of geriatric medicine.

Reporter Jang Jong-ho bellho@sportschosun.com

This article has been translated by GripLabs Mingo AI.