Effects of road lighting on motorways.
OBJECTIVE
The study has three objectives. The first is to investigate how the effect of road lighting on motorway accidents varies with different weather and road surface conditions. The second is to evaluate the future benefit of road lighting as a safety measure on motorways. The third is to evaluate the need for further research in the field of motorway lighting.


METHODS
This article presents a cross-sectional study of the effects of road lighting on motorways mainly in The Netherlands. The main source of data is a Dutch database of accidents covering the period 1987-2006, but British and Swedish data are also used.


RESULTS
The effect of road lighting on motorways is found to be greater in The Netherlands than in Great Britain or Sweden. Reasons for this are not known. Effects are found to vary according to background characteristics and are lesser during precipitation than during fine weather and on wet road surfaces than on dry surfaces. No effect of road lighting is found during fog. Collision with light poles constitutes a large number of accidents on lit motorways and reduces the safety effect of road lighting.


CONCLUSIONS
The effect of road lighting on injury accidents during darkness is found to be very high (-49%) on Dutch motorways. However, the effect seems to vary between countries. Collisions with light poles reduce the effect of road lighting. Road lighting will probably be an effective safety measures on motorways for many years. In the long term, however, the benefit of road lighting will probably be reduced along with the implementation of new vehicle and road technology. Modern technology permits a continuous adaptation of luminance levels to optimize the effect of road lighting on safety while at the same time minimizing energy consumption. However, more detailed knowledge concerning the effects of road lighting at different lighting levels is needed in order to use this technology effectively. Alternative or additional measures like LED guide lights and light road surfaces also need to be evaluated.
Wanvik
Per Ole
PO
Norwegian Public Roads Administration, Region South, Serviceboks 723, Arendal, Norway. per.wanvik@vegvesen.no
D000063:Accidents, Traffic / Q000517:prevention & control; D001334:Automobile Driving; D003430:Cross-Sectional Studies; D008027:Light; D009426:Netherlands; D016017:Odds Ratio; D012449:Safety; D013499:Surface Properties