Research on the link between vehicle accidents generally shows a higher proportion of accidents at night. A study in 2005(1) showed a disproportionate number of young drivers, especially young men, are injured at night. In discussions with them the most striking point was how many young males like to ‘test’ themselves and their cars to the limit!

Focusing specifically on The Impact of Street Lighting on Night-Time Road Casualties, the Transport Research Laboratory (TRL) in March 2009, this research carried out for the Department of Transport concluded: “The detailed analyses of the data acquired for local authority areas and parts of the national road network were unfortunately not successful in demonstrating an accident reduction due to lighting…. In all cases except one, the modelled differences in accident density between lit and unlit sections were lower at night, which would infer that the effect of lighting was to increase the accident density.”(2) 

Later extensive research in 2015 examining 62 local authorities areas where they had instigated street lighting switch offs, part-night lighting, dimming and replacing yellow/orange with white lighting, showed no increases in night-time vehicles accidents.(3) 

The accepted norm is that lighting contributes to a 30% average reduction in night-time accidents, but this research stems from the 1950-70s. The later research (above) demonstrates the direct link between road lighting and accidents rates is far more complex, with many variables behind why accidents occur. Certainly the most recent research shows that where communities would like less road lighting to enhance dark skies, vehicle accidents rates should not be used as a factor to prevent beneficial changes. 

Header image: 'Light pollution taken from Kendal Castle' kindly supplied by Stuart Atkinson - 29th May 2020