Visibility and discomfort glare of LED road studs

Traffic management and road safety may benefit from self-powered LED road studs but to be effective they need to be visible to road users, without glare, whatever the environmental conditions. Some parameters, such as dry versus wet road surfaces, have not been investigated previously for LED installations. In this context, two experiments have been conducted to study the visibility and discomfort glare produced by a LED road stud. The results suggest tuning the luminous intensity of LED road studs according to the illumination and road surface conditions to ensure visual perception by road users while controlling energy consumption. A quantitative model is provided in order to link the dimming to the environmental parameters.