Some of the factors affecting the visibility of older drivers in night driving are described such as contrast threshold, disability glare, and discomfort glare.

Headlamp, vehicle and environment factors such as headlamp mounting height, rearview mirror reflectivity, headlamp cleanliness and the reflectivity of objects on and about the roadway are evaluated.

The effects of these variables on the visibility and comfort of older drivers are described and suggestions are made on ways to improve the night driving safety of older drivers.