The safety of highway junctions in Finland was studied with the help of predictive accident models. The districts of the Finnish Road Administration (FinnRA) undertook an inventory of all at-grade junctions of major roads in the summer of 1988. The inventory, which included a total of 2,700 junctions, provided data for modelling. The data included police reports of accidents and accident victims taken over a 5-year period. The variation in the number of accidents was explained using traffic volumes and the variables collected in the junction inventory. Only junctions that had no major changes during the study period were included in the models. The report describes the method for obtaining a reliable estimate of the expected number of accidents at a single junction based on the accident models and the observed number of accidents in the past. These estimates were used in assessing the effects of a number of frequently used safety measures at junctions. An estimate of the most probable safety effect and the confidence limits of the estimate are given for each of these effects. (A)
Abstract