Analysis of Retroreflection Coefficient Influenced by Vehicle Headlamps

Retroreflective sheetings were used widely in road signs, through the reflection of vehicle head lamp, this material would reflect higher brightness when reverse the direction of incident, this characteristic can provide messages to driver more clear and further. For the different reflectance spectra, these materials show colors as white, yellow, blue, and so on. Recently Xenon lamps were used as vehicle headlights; the difference of light sources spectra lead to the change of the retroreflection coefficient, with identical light path geometry, incident flux, and tested sample. In this experiment, the emission spectra of Xenon lamp and Halogen lamp and reflective spectra of white, yellow, and blue sheetings were tested through spectrum superposition, the relative retroreflection coefficients were gained, white sheeting shown similar retroreflection coefficient for its whole visual reflective spectrum, other monochromatic sheetings shown different influence, the quantity of retroreflection coefficient with higher gain than Halogen lighting.