LED lighting or Light Emitting Diodes is a type of light source that is starting to be used in larger scale on pedestrian and bicycle lanes in Sweden and elsewhere. The project's aim was to study the traffic safety aspects of new lights and the interaction with the street environment for pedestrians and cyclists.
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This project investigated the lighting conditions, effects on cyclists, and the interactions between lighting, traffic safety, street environmental conditions and/or other effects such as perceptions of safety for three different light sources (mercury vapour 125W, ceramic metal halide 70W and LED 25W) located in about the same type of street environment on a pedestrian and bicycle path on the Kungsholms strand in Stockholm.
Results show that the energy consumption of the LED lighting is 28% of the traditional mercury vapour lighting and 49% of ceramic metal halide lighting. LED may have slightly lower levels of illumination but with good light distribution of the luminaire, it is possible to achieve good uniformity. This study shows that it is possible to obtain sufficient uniformity levels with LED lighting but that the levels are dependent on the luminaire design, pole design and the number of poles per meter road (in this study the pole spacing was 15.3m). The number of LED poles required along a distance is higher than necessary for mercury vapour lighting and ceramic metal halide lighting, which currently makes the LED more expensive per kilometer illuminated path. The advantages of LED lightings are that the longevity is so much longer that in the longer time-scale perspective, it is possible to make substantial savings on energy, operating and maintenance costs.
There may be adverse effects of new energy-efficient lighting (on the number of single-vehicle accidents or perceptions of safety) if the pole spacing, illumination or uniformity is under dimensioned or if the fixture does not allow for good light distribution or if installations occurs in environments with many objects or other things that block the view. This study demonstrated no difference in cycle speed for LED lighting between daylight and darkness, or between different types of lighting.
Policies focusing on what is an acceptable lighting viewed from a combined view of traffic safety and perceptions of safety are currently missing, but is of high relevance for more energy efficient lighting. Without better guidance for the perceptions of safety there is a risk of installing new lighting with too low levels of illumination, thereby making the road and its surroundings less safe and unattractive for unprotected road users.