Influence of coloured light projected from night-time excessive luminance outdoor LED display screens on vehicle driving safety along urban roads

Night-time excessive luminance Outdoor LED display screens (OLDSs) are widely used in urban areas, which yield potential safety hazards to vehicle traffic at night. In this study, we evaluated the effects that coloured light projected from excessive luminance OLDS has on vehicle driving safety along urban roads at night. Based on road lighting environmental characteristics at night and using reaction time (RT) testing software under different white field luminance (WFL) conditions, the RTs for small targets (STs) with different colours of OLDS were examined. First, in combination with field tests, excessive luminance values of typical OLDSs at night (1,000, 3,000, and 5100 cd/m(2)) were determined; then, experimental simulation scenes were established by integrating real photos with software simulations. Next, the RT experiments were conducted, followed by obtaining the influences that different colours have on the RTs and visual missing dots (MDs) under different WFL conditions. The results showed that, in addition to blue light, the coloured light of OLDSs can improve a driver's ability to recognise small targets and reduce RTs in the case of low WFL values, but the coloured light causes more MDs and affects traffic safety. The findings also indicated that the night recognition abilities of females under the influence of projected OLDS coloured light was better than that of males.