Preferences for Headlight Swivel Angles at Curves on Rural Two-Lane Highways

Abstract

Drivers' preferences for headlight swivel angles were investigated as a function of curve alignment and assessment point before the curve section. In a field experiment using a test vehicle at the test track of the Denso Abashiri Test Center in Hokkaido, Japan, 33 young drivers were surveyed on their headlight swivel-angle preference at three assessment points before each curve. The subjects stopped at each assessment point and selected the preferred low-beam swivel angle from the swivel angles presented. Curve alignment and assessment point were found to have a marked effect on preferred swivel angle. A multiple regression model was developed for estimating optimal swivel angles. It was found that headlight swivel should be predictive toward assisting the driver's judgment of curve sharpness before the curve section. In the near future, headlight swivel systems incorporating a dynamic algorithm should be able to predict the road geometry before arrival at the curve, with the aid of commercial car navigation systems.