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The literature on headlamp aiming is surveyed in detail to pinpoint the various sources and magnitudes of aim variance. Four major sources of variance are identified (differences between beam and mounting plane, photometric changes in use, long axis alignment, and human factors), along with a number of others of lesser consequence. Illustrations are offered showing the expected population variance under a variety of conditions. It is apparent that, at the present state-of-the-art, a substantial percentage of the lamp population can be expected to be beyond the limits recommended in SAE J599c. It is further apparent that this would be true regardless of whether or not a vehicle inspection program is in operation. Recommendations are given regarding research emphasis in headlighting. Ways of reducing variance from the most significant sources are considered and recommendations offered.

This paper surveys the literature on motor vehicle headlighting and its influence on the ability of drivers to avoid accidents. The review identifies the key relationships between headlamp design characteristics and driver and environmental factors. The major safety problems associated with headlighting are discussed, and issues needing the attention of the research community are identified.

This paper addresses the relationship between vehicle rear lighting and signaling systems and probability of accident involvement. All classes of vehicles and all aspects of rear lighting and signaling systems as specified in current standards are considered in terms of the informational needs of following drivers. Relevant vehicle, driver, and environmental characteristics are identified, and their frequency of occurrence and relationship to accidents (or pertinent proxies) discussed whenever such information is available. The bulk of the report is devoted to reviewing, summarizing, and integrating the large body of data concerning vehicle rear lighting and signaling systems, including engineering analyses and other analytical studies, as well as experimental data from laboratory, simulation and field studies.

Older persons often give up or greatly reduce driving during the hours of darkness. The reason for this is apparently age-related changes in vision that are most noticeable under conditions of low illumination. This paper reviews research that shows how the nighttime visual performance of older drivers can be aided. Improvements discussed involve the detection and legibility of highway signs and the detection and identification of potential hazards such as large trucks.

LEDs have been developed that are suitable for use in automotive signal lamps. As signal light sources, LEDs have a number of advantages, among which are faster rise times, long life, flexibility in lamp size and shape, and the possibility of unique modes of presentation that may improve signal performance. The purpose of the research described in this paper was to examine driver preferences and response time to unique stop and turn signal presentations using LED sources. The results suggest that subjects preferred some of the signal modes to present-day configurations, and responded faster to them under a variety of conditions.