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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.

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.

A nationwide survey was conducted of the condition of vehicle lighting equipment. Twenty different sites were visited and a total of nearly 1, 000 vehicles included in the sample. Headlamp aim and dirt levels were measured and the condition of marker and signal lamps noted. The results of the survey indicate that many vehicles have headlamps that are badly aimed. The condition of front and rear marker and signal lamps is generally good, with more than 98% of such units functioning. Side marker lights were in poorer shape, hut more than 90% of these were operating. Consistent differences were found between areas with and without vehicle inspection programs. It appears that such programs are effective in improving the condition of vehicle lighting systems.

This report describes a test run on a device (the Advance Braking Light Device, or ABLD) that senses the rate at which the accelerator is released. If the rate is equal to or faster than a predetermined minimum the device turns on the brake lights for one second. The interest in this study was in determining whether there were any operational problems with the ABLD, and measuring the gain in brake illumination time it provides. The results suggest that there are no significant operational problems, and that the device causes the brake lights to be illuminated 0.2 to 0.3 second sooner when it is energized.

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.

Glare can come from sources in front of or behind a vehicle. Most attention has been paid to the problem of glare from oncoming vehicles. Yet glare from following vehicles can be just as severe, and continue for longer periods of time. This paper examines the problem of glare from the rear view mirrors, both from a point of view of its effect on visibility and discomfort. It is shown that such effects can be quite significant. Methods of reducing the glare levels are discussed.