A prototype adaptive front-lighting system (AFS) featuring a modified light distribution below the cut-off line was manufactured to test bending lamps in the road environment of Japan. To ensure an illuminance of 50 lx or more in the eye focus area during low- or mid-speed cornering, the basic light diffusion patterns of gas-discharge headlamps were examined. It was found that if the diffusion becomes excessive, the far visibility decreased and the overall illuminance of the visible field decreases. To overcome this problem, additional lamps were introduced to ensure sufficient illuminance by reducing the light diffusion requirement of the headlamps. A reflector-swivelling capability was also provided to the additional lamps. In the prototype, control of the bending lamp is a response to the input of steering angle and vehicle speed data. The prototype was tested on prefectural road 75 in the Takayama district of Shimizu City using five participants with normal eyesight. The participants indicated that cornering visibility was improved by AFS. Luminance contrast and road surface illuminance in the eye focus area were increased by AFS. Road curve lines became more easily recognisable. The eye focus moved closer to the daytime eye focus position. The quantitative evaluation was in agreement with the participants' perceptual rating. For the covering abstract see ITRD E123380.
Abstract