Summary

Headlight glare is a significant safety problem, both in reality and perception. In reality, glare is a physiological problem brought on when Glare is caused by scenes in the visual world that contain relatively small luminous elements with high photometric brightness compared to their surroundings, resulting in difficulty with visual adaptation to ambient light. In perception, through logbooks and conducting focus groups, researchers have found that 29% of older drivers perceive headlight glare as their primary nighttime driving concern. Matching reality to perception, therefore, means that glare is a problem, is recognized by drivers, and it is ever growing. Also, care must be taken in research to correctly address glare. While it is optimal to address both in any countermeasure, countermeasures to disabling glare have a direct effect on driving safety and to reduce this is the primary target of this research. This research approach is geared toward directly addressing safety issues with glare—and is therefore conceived to address glare through a three-pronged project:

1. Developing a novel surface treatment to improve glare paddles,
2. Assessing whether more pervasive mainline lighting, particularly at horizontal curves in urban areas, is a viable countermeasure, and
3. providing to Caltrans a computer-based "glare tool" to evaluate current alignments and sight lines for susceptibility to glare.