Study on Visibility and Discomfort Glare of Adaptive Frontal Lighting System (AFS) for Motorcycle

When a is driven on a curved road, the headlamp inclines horizontally as the body banks, and the area illuminated by the headlamp becomes limited. Therefore, minimizing the horizontal inclination of the headlamp would improve the visibility. This study was conducted to clarify the effects of a system to adjust the horizontal inclination of the headlamp (hereafter, motorcycle AFS) on visibility for the rider, and to examine the side-effects of the AFS (e.g., discomfort glare for oncoming drivers). The study included the following two parts: (1) A simulation survey and an actual driving survey to test the visibility demonstrated that a AFS enhances visibility for the rider while the is being driven on a curved road. When the horizontal inclination of the headlamp is adjusted by the same or greater amount than the bank angle of the body, the visibility evaluation scores are equal to or above the just acceptable level. However, when the adjustment amount is less than the bank angle, the visibility evaluation scores are below the just acceptable level. (2) A simulation survey and an actual driving survey to evaluate the discomfort glare showed that when the horizontal inclination of the headlamp is adjusted by the same or smaller amount than the bank angle, the glare evaluation scores are equal to or above the just acceptable level. However, when the adjustment amount is more than the bank angle, the glare evaluation scores are below the just acceptable level. Based on the results obtained in this study, the following technical requirement is proposed for the AFS: A horizontal inclination adjustment system (HIAS) may be installed. However, the adjustment amount of horizontal inclination shall not exceed the vehicle's bank angle. The full text of this paper may be found at: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv21/09-0385.pdf For the covering abstract see ITRD E145407.