Off-Road Screening Tests Can Identify Impaired Driving Among Older Adults

By Lisa Rappaport

July 08, 2020

(Reuters Health) - Off-road driver screening tests can reliably identify older adults who are likely to fail on-road driving tests, an Australian study suggests.

Researchers examined results from on-road driving tests for 560 drivers who also completed off-road screening tests including the Useful Field of View (UFOV), DriveSafe/DriveAware, Multi-D battery, Trails B, Maze test, Hazard Perception Test (HTP), DriveSafe Intersection Test, and 14-item Road Law test.

On-road tests were administered by occupational therapists who were blinded to the outcomes of the off-road assessements. Participants, who ranged in age from 63 to 94 years, completed 50-minute open road tests in vehicles with automatic transmission and dual brake controls. Driver safety was scored on a scale of 1 to 10, with scores of 1 to 3 indicating major errors and unsafe behavior.

A total of 68 drivers (12.1%) were classified as unsafe based on the on-road tests.

All the off-road tests predicted on-road performance. While none of the individual tests had high positive predictive value, they all had high negative predictive value of greater than 90%.

In multivariate analysis, a combination of Multi-D, UFOV, and HTP remained significant when all variables were tested simultaneously with complete case analysis, with an area under the curve (AUC) of 0.89. This model provided an estimated specificity of 84.1% and an estimated specificity of 80.4%.

Of all the assessments, the Multi-D battery was the most accurate individual test for picking out unsafe drivers, with an AUC of 0.85, sensitivity of 77.1% and specificity of 82.1%.

"These results are important because with an ageing population, we need to be able to detect unsafe drivers efficiently and cost effectively," said study coauthor Kaarin Anstey, director of the Ageing Futures Institute at the University of New South Wales in Sydney.

"The gold standard of an on-road driving test is expensive and there are limited qualified occupational therapists, so this assessment may not even be available in many regions," Anstey said by email. "The findings of this study provide much stronger evidence of the efficacy of (off-road) tests because we evaluated them on by far the largest number of participants to date, and we also evaluated them in subgroups with cognitive impairment and eye disease."

Out of 560 study participants, 105 people had cognitive impairment and 124 individuals were vision impaired.

In the group with vision impairments, all the off-road tests except the 14-item Road Law Test and the DriveSafe Intersecetion Test predicted safe driving in the on-road test.

Among people with cognitive impairment, several tests including the Maze Test, UFOV, and DriveSafe Intersection Test didn't correctly identify unsafe drivers.

Study participants were not randomly selected, they were recruited by advertisements and might not be representative of the older driver population, the study team notes in JAMA Network Open.

The researchers also didn't link outcomes to state crash records or follow drivers over time to determine how test results lined up with actual driving outcomes.

Even so, the results may help clinicians identify older adults who are at risk for unsafe driving, said Ediriweera Desapriya, a research associate in the Department of Emergency Medicine at the University of British Columbia in Canada, who wasn't involved in the study.

"Accurate and evidence-based screening tools such as described in this new study may influence clinicians to screen and identify more high risk drivers and remove them from the road timely appropriate manner," Desapriya said by email. "However, in order to increase screening for unsafe drivers, clinicians may need additional monetary compensation for older driver assessment, enhanced training how to use these tools effectively and efficiently, simplify unsafe driver reporting requirement and the process and the availability of enhanced alternative older driver safe mobility options."

SOURCE: JAMA Network Open, online June 17, 2020.