Vital Effects of Applied Lighting Science in Road Engineering

In the eighties of the last century, at one of the many traffic nodes that lead to the Paris-Lyon highway, those concerned noticed that the rate of accidents at night is 600% higher than at other nodes whose design does not differ much from the aforementioned node. The matter remained for years without a convincing explanation until, by chance, some of the lighting poles leading to the aforementioned node broke down. Those concerned noticed that the accident rate had decreased significantly, then returned to its previous rate after the defect was fixed. Here, those old studies that were conducted during World War II on the physiology of lighting color and its environmental effects came back to mind. What is noteworthy is that the flood lighting of that traffic node was increasing by six to seven times the recommended international rate, which means that the concept of a smooth gradation of lighting intensity levels was not taken into consideration.