Contrast Sensitivity for Drifting Sine Wave Gratings in Near Visual Periphery Predicts Older Drivers Accident Risk

Drivers over the age of 70 have a significantly higher rate of intersection collisions than younger drivers. Many of their accidents involve a visual detection error, resulting in a right-of-way violation and a collision with an oncoming vehicle.;Three studies relating older drivers' peripheral motion detection to accident risk demonstrate that peripheral motion contrast threshold (PMCT) for low spatial frequency drifting sine wave gratings significantly declines with age, and that PMCT predicts about 40% of driving performance variance (p > .001). Approximately twenty older drivers participated in each study.;In all three studies, older drivers' PMCT was assessed using forced choice psychophysical procedures, with 0.4 cycle/degree sine wave gratings drifting at 13.75 or 27.5 degrees/second. The stimulus spanned 5 or 10 degrees of visual angle and was presented at 10--20 degrees of retinal eccentricity. Useful Field of View (UFOVRTM) was also assessed in the second and third studies.;The first and second studies used a bespoke driving perception questionnaire to measure accident risk, and the second study validated that questionnaire against an abridged Manchester Driver Behaviour Questionnaire. The third study's measure of accident risk was driving simulator performance (i.e., driving examiners' assessments and crash counts). PMCT and UFOVRTM predicted accident risk equally well.;Future work will include development of a practicable two-minute version of the PMCT for use by DMV staff and clinical practitioners.