Dynamic public lighting (DYNO) : cover report

The Directorate-General for Public Works and Water Management is considering the feasibility of dynamically switching the lighting on motorways (DYNO). This would provide under all traffic and weather conditions adequate illumination levels without illuminating the road unnecessarily brightly. This has been put into practice in a test conducted under contract of the Ministry of Transport, Public Works, and Water Management, Transport Research Centre into the effect of dynamic illumination of public highways on driving behaviour and traffic safety. The first step was to establish, on the basis of a road characterization analysis, a preliminary switching schedule. Besides the normal lation (100%) a reduced (20%) and an increased level (200%) was employed. Depending on traffic and weather conditions, a suitable level is switched on. The preliminary switching schedule was employed in the test, during which its effect on driving behaviour was examined. The results demonstrated that the normal level of illumination resulted in minor accommodations of behaviour: average speeds increased somewhat (ca. 0.7 km/h) and the number of critical situations (short traffic intervals, short TTCs) increased by a maximum of 1%. Taking also the positive effect of conventional lighting on traffic safety known from the literature, no negative effect on traffic safety is anticipated from those accommodations of behaviour.
Differences between 100% and 200% were not reflected in driving behaviour for the combination of high traffic volume and precipitation. Other situations for which the preliminary switching schedule of 200% is prescribed are relatively rare and the increased benefit of a higher level of illumination in such situations is considered to be limited. An inquiry into motorists' perceptions of dynamic illumination of public highways showed that it enjoyed their broad support. There is absolutely no evidence to support the contention that the reduced level of illumination will under favourable circumstances be perceived as being too low. A cost-benefits analysis was addressed to the relationship between the installation costs of DYNO (20-100-200) for the trial location and the energy and environmental costs (CO2 emissions from the power station). It showed that both the installation costs and the energy and environmental costs were higher than for a conventional installation. This system will therefore be unable to recover its investment on the basis of energy and environmental costs. Even when the DYNO system is fitted only with reduced and normal levels, the installation costs will still be higher than for a conventional installation, but the energy ant the energy and environmental costs lower than for a conventional installation. Due to this the system can in principle recover its investment on the basis of energy and environmental costs. This is compatible with the government's policy of reducing CO2 emissions. The payback period will depend strongly on the local situation and the tariff structure in which the system is employed.