Research on the nighttime visibility of white pavement markings

At night, clear pavement markings are essential for driver safety. Currently, markings visibility evaluation relies on the retroreflectivity, but the impact of line width is unclear. To quantify the impact of line width on visibility and to refine visibility evaluation methods, a driver visual detection experiment was designed using both qualitative and quantitative approaches. Twenty-four drivers of small vehicles were randomly recruited to participate in visual detection tests of a total of 54 white pavement markings (comprising 6 widths and 9 retroreflectivity levels) under the illumination of high beams, following the principle of using the "emergence point" as the critical state for assessing pavement marking visibility. This study indicated that widening pavement markings significantly enhances their visibility, particularly for markings with low retroreflectivity. A visibility evaluation model was established to quantify the impact of width and retroreflectivity on the visual distance of markings. The model confirms that widening markings can improve visibility, thereby reducing the required level of retroreflectivity. The research methodology and findings provide technical support for managers to more accurately assess nighttime safety visibility during pavement marking operation and maintenance.