Roles of motion perception and visual acuity for driving hazard perception

Abstract

PURPOSEThere are many visually impaired people who can drive legally with bioptic telescope. Drawing on the experience of drivers with reduced vision, this study investigated the role of motion perception and visual acuity in driving, under simulated low visual acuity.METHODSTwenty normally sighted participants took part in a driving hazard perception (HP) test, in four different conditions: with/without motion interruption and with/without simulated low visual acuity. In interrupted motion conditions a mask frame was inserted between every frame of the driving videos. In simulated low visual acuity conditions, participants wore glasses with diffusing filters that lowered their visual acuity to 20/120 on average. Participants’ response time, hazard detection rates, and HP scores, which combined response time and detection rate, were compared.RESULTSRepeated measure ANOVA revealed that the HP scores significantly declined from 20.46 to 16.82 due to the motion mask (F(1,19)= 9.343, p = 0.006). However, simulated low visual acuity did not affect HP scores (F(1,19) = 1.807, p = 0.195). The interaction between vision and mask was not significant (F(1,19) = 1. 295, p = 0.269). The decline in score was mostly due to significant decrease in detection rate, from 0.80 to 0.64, due to the motion mask (F(1,19) = 16.686, p = 0.001).CONCLUSIONSIn this experimental setting, human observers relied largely on motion information for detecting driving hazards, rather than high visual acuity. This finding might help explain how visually impaired drivers can compensate for their impaired vision during driving.