Current U.S. regulations require that if vehicle low beams and high beams are provided by separate headlamps arranged horizontally, "the lower beam shall be provided by the most outboard headlamps". One possible rationale for this is that drivers may use the angular separation between headlamps as a cue for the distance to an oncoming vehicle. The present study was designed to investigate this rationale by evaluating the extent to which peoples' nighttime distance judgments are influenced by low-beam headlamp separation. To do this, the authors performed two field experiments, in which the subjects had to make judgments about the distance to a vehicle seen in the oncoming lane of a two-lane road at night. The results of the two experiments are discussed.
Samenvatting