Real-world use of high-beam headlamps

Abstract

Drivers in this study participated in a field operational test of two crash warning systems and were unaware that data about their high-beam use were being collected. Drivers were given instrumented vehicles to drive as their own car for periods ranging from 7 to 27 days. Most of the driving was in southeastern Michigan. The results indicate that high-beam headlamp use is low, a finding consistent with previous studies that used different methods. Combined over all drivers and all road types, high beams were used for 3.1% of the distance driven at night. Drivers used high beams most frequently on local roads, but even that use was only 8.9%. Under the most favorable conditions for high-beam use (rural roads with, no opposing or preceding vehicles), drivers used their high beams 25.4% of the nighttime distance driven. Older drivers used high beams three times more frequently than did younger drivers, suggesting that older drivers, to at least some extent, understand their visual impairment at night, and therefore take some compensatory measures. Because low beams do not provide sufficient illumination in many driving situations, the present findings imply that (1) increased high-beam use should be encouraged and (2) the use of automatic switching between high and low beams is likely to be beneficial.