Rearview Mirrors and Visual Performance: The Role of Afterimages

The visual afterimage that results from directly viewing headlamps in a rearview mirror reduces the visibility of objects on the line of sight for up to several seconds after a driver's gaze is redirected to the roadway. Reaction times to detect and recognize simulated potential roadway hazards were measured for three levels of relected glare (1, 2, &3 lux) under low luminance and contrast conditions similar to what might be experienced on rural roadways. By reducing reflected glare from the mirror, reaction times decreased by up to 1.4 seconds under the lowest constrast condition which, at 100 kph, increases the distance at which hazards can be recognized by about 30 meters.