A brief peripheral motion contrast threshold test predicts older drivers’ hazardous behaviors in simulated driving

• We test if motion sensitivity is associated with older driver performance.
• We use an optimal stimulus to measure magnocellular function in isolation.
• Older driver performance during simulated driving is examined.
• Declines in motion sensitivity are associated with more crashes in older drivers.
• A faster version of a previous motion sensitivity test is validated.

Our research group has previously demonstrated that the peripheral motion contrast threshold (PMCT) test predicts older drivers’ self-report accident risk, as well as simulated driving performance. However, the PMCT is too lengthy to be a part of a battery of tests to assess fitness to drive. Therefore, we have developed a new version of this test, which takes under two minutes to administer. We assessed the motion contrast thresholds of 24 younger drivers (19–32) and 25 older drivers (65–83) with both the PMCT-10 min and the PMCT-2 min test and investigated if thresholds were associated with measures of simulated driving performance. Younger participants had significantly lower motion contrast thresholds than older participants and there were no significant correlations between younger participants’ thresholds and any measures of driving performance. The PMCT-10 min and the PMCT-2 min thresholds of older drivers’ predicted simulated crash risk, as well as the minimum distance of approach to all hazards. This suggests that our tests of motion processing can help predict the risk of collision or near collision in older drivers. Thresholds were also correlated with the total lane deviation time, suggesting a deficiency in processing of peripheral flow and delayed detection of adjacent cars. The PMCT-2 min is an improved version of a previously validated test, and it has the potential to help assess older drivers’ fitness to drive.