The objective of this study was to find the parameters of the road geometry and road surface condition that have effect on the run off the road accidents on motorways in Finland. The study was executed by comparing the road parameters with the accident rates of road sections. The geometrical parameters studied were curvature and hilliness and also the crossfall and gradient. From these values the positive (right curve, uphill) and negative (left curve, downhill) were studied separately. The curvature seems to have some effect on accidents but hilliness not. The problem is that on motorways the design standards are so good that there is very little variation and the curves are mostly very smooth. The studied pavement condition data (rut depths and IRI) might have a little effect on the accidents. The problem with the pavement condition variables is that they are dependent on time. The measurements are done twice a year on motorways so there might be several months between the measurement and accident. In some cases there might have been even repaving done. (A). For the covering abstract of the conference see E216632.
Samenvatting