This is a final report of the Nordic project "Utformning av förlatande sidoomrade" (Design of forgiving roadside area) which was launched in 2005 by Swedish, Norwegian, Danish and Finnish road authorities. Main objective of the project was to evaluate the safety of different roadside ditch and slope profiles. For this purpose a number of simulated tests were conducted. The analyses in this report are based on data from these simulations together with the results of full-scale tests performed in Finland and Sweden during years 2000-2001. As a background data for the analysis detailed statistics of single vehicle accidents and applicable results of earlier research was collected. The analysis of roadside area includes several ditch profiles with 4.0 m high backslopes, ditch profiles in front of rock or concrete wall, ditch terminations at minor road junctions and embankment slopes (fill slopes). In most cases risk analysis was used to evaluate the safety of tested roadside profiles. In the analysis the likelihoods and severities were defined for following incidents: 1) Crash into the backslope 2) Rollover 3) Crash into rigid obstacle on backslope at height of 1 ,2, 3 or 4 meters 4) Collision with another vehicle when coming back onto the roadway. The aim was to find answers to the questions like "How to design the ditch if the distance from the edge of the road to the rigid obstacle is 5, 7, 9 or 11 meters?" For presentation of the results also new methods were developed. Result tables and risk matrices make it possible for the reader to carry out additional or detailed analyses. This report may be found at http://alk.tiehallinto.fi/julkaisut/pdf2/3201124e-v-safety_of_roadside_…
Abstract