Measurement and evaluation of the road lighting in mesopic and photopic vision

Recently, more and more experts deals the issue of road lighting. They design methodologies that should be following in the design of public lighting. According to the latest norms is a way of designing road lighting more efficiently, contributing to safer operation and eliminates distracting light. The roads lighting is a specific case of lighting system where an observer stands in the area of rather low adaptation luminance. That means that lighting parameters of roads lighting system are not evaluated according to the photopic curve of human eye sensitivity but according to curves that can be found in mesopic area of sensitivity. Based on this knowledge, it was realized measuring the lighting of the road on which the illuminance evaluated using mesopic sensitivity curves of the human eye. These were selected according to the size of the adaptation luminance, which the observer is exposed. The problem is that the eye provides information in the foveal region where no rods. However, the vision of the driver is also involved in the peripheral portion of the retina, where the rods are.