Joel Devonshire

Effects of Automotive Interior Lighting on Driver Vision

Abstract There has been growing interest in vehicle interior lighting for both functional and aesthetic purposes. Although there is a large body of research on nighttime driver vision and vehicle exterior lighting, there has been little research attention to vehicle interior lighting. This report includes a brief review of some of the research that has been done, and presents the results of a nighttime field study that was performed to contribute to the understanding of how vehicle interior lighting affects some basic aspects of driver vision. Participants in the study were asked to perform two tasks while seated in a stationary experimental car on a closed test road at night: 1) detecting pedestrians on the road ahead, and 2) rating the subjective brightness of a reflected veiling light on the windshield. The veiling light was varied in both luminance and color. The results indicated that pedestrian detection was closely related to photopic photometric measures, suggesting that the pedestrian task was influenced primarily by cone photoreceptors, while the rating of subjective brightness appeared to show an influence of rod photoreceptors. These results have implications for how the photometry of vehicle interior lighting should be performed in order to best correlate with driver visual performance. Future research should further quantify the effects observed here and investigate changes in retinal adaptation associated with automotive interior lighting.