Citation

Janoff MS. Transp. Res. Rec. 1988; 1172: 88-92.

Copyright

(Copyright © 1988, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Extensive research has indicated the existence of adverse neurological effects of flickering or rhythmic lights, referred to as photic stimulation. Although regularly flickering light rarely exists for more than a few seconds in the natural environment, some types of artificial lighting, such as that found on long bridges or in long tunnels, can provide a photic stimulation for a sufficient time (i.e., minutes) to cause such adverse effects. These effects, theoretically, could result in an increase in nighttime traffic accidents. About 20 years ago, a few highway agencies began to design and install low-mounted, lineal-type lighting systems--almost all of which produce a flicker--on a number of bridges under the assumption that such lighting was an improvement over conventional lighting systems. This assumption was never validated. One such installation was the San Mateo Bridge over San Francisco Bay. Theoretically, the length of this bridge should provide sufficient exposure to this lighting to induce the adverse neurological effects. The availability of detailed accident records for the San Mateo Bridge provided a basis for determining whether the nighttime safety on this bridge was in any way related to the amount of time a motorist was exposed to this lighting system. The analyses of the accident data have shown that the nighttime safety on the bridge has been adversely affected by the lineal lighting, that the effect occurs after only about 3 min exposure to the lineal lighting, and that replacement of this type of lighting with conventional overhead lighting promotes a safer nighttime traffic environment.

Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1988/1172/1172-011.pdf

Language: en

Keywords

Accident Prevention; Bridges, Highway; Electric Lighting--Outdoor; Highway Accidents--San Francisco, CA; Illuminating Engineering; Visibility--Flicker Effects