Computational simulation of night vision of retroreflective road markers under poor atmospheric visibility

摘要

A method is developed and investigations of the contrast and limiting visibility range of a retroreflective marker defining, for example, the overall-dimensions of a heavy truck are carried out for a case of illumination by anti-fog headlamps, upper or low beam of another vehicle through fog of various optical density with no other external lighting. The studies simulate night vision of non-Lambertian road markers from the viewpoint of the modern image transfer theory. The method enables one to include analytically the effects of multiple light scattering by fog aerosols, different mutual positions of the headlamps, vehicle driver, and object observed, as well as real retroreflective properties of the marker to derive vision characteristics via quite simple formulas. The visual contrast and limiting visibility range values of, respectively, retrorefractive and Lambertian markers are compared to demonstrate the advantages of applying the former for enhancing traffic safety and increasing allowable road speed. The recommendations are made with respect to the use of retroreflective markers as an auxiliary signaling means to show the overall dimensions.