This paper describes several studies of headlighting and glare effects. It starts with a seeing-distance study, the results of which show that low-beam headlighting systems do not provide adequate illumination to reliably reveal low-contrast objects at any but relatively low speeds.
The major barrier to increasing headlamp output is concern over glare effects. This paper describes two studies of glare. The results suggest that judgments of glare discomfort are influenced by the range of glare stimuli to which subjects are exposed, and that people are more tolerant of glare than previous laboratory studies indicate.
A reanalysis of some field glare and illumination measurements is also offered. This points out the difficulties in controlling glare under real-world operating conditions.
Recommendations are offered for a program that would move toward eventual achievement by an optimum low-beam lighting system.