Accidents are often related to high speed and it is well documented that even small reductions in speed can produce a significant decrease in the number of accidents. It is therefore of interest to compare the safety on specific part of the roads (in this case junctions) on which different speed limits are used. In this study, the comparison has been made for 4-armed signalised junctions. The study includes a total of 350 urban junctions situated on roads with speed limits of 50, 60, 70 and 80 km/h and 142 rural junctions with speed limits of 60, 70 and 80 km/h. The accident risk for each junction-group is estimated using generalised linear modelling techniques and by using accident frequencies (the average number of accidents per 1 million incoming vehicles). Both methods indicate a clear relationship between speed limit and accident risk: The higher speed limits, the higher accident risk. Junctions situated on 80 km/h roads have a significant higher accident risk than all other junctions, where as the accident risk at junctions with lower speed limits (50-70 km/h) does not differ significantly. If the accident risk is based on the number of killed and serious injured, the relationship between speed limit and accident risk is even stronger, especially for junctions in rural areas. (A)
Abstract