Roadside accidents happen when a vehicle runs off the road. The majority of these accidents are very severe because leaving the road is usually followed by hitting a solid obstacle (tree, pole, support, culvert front wall, barrier). Roadsides are some of the most important issues of road safety. They have been studied for years to identify roadside hazards and the effectiveness of road safety measures such as restraint systems. While restraint systems prevent crashes into obstacles or running off the road down steep slopes, they are obstacles themselves. If wrongly designed and located, restraints may pose a serious risk to the safety of road users. Examples of safety barrier models were analysed to understand how barriers change safety. It was found that the models differ and use different methodologies and data. In building a new analytical tool, the models’ differentiating factors were combined to create a comprehensive model to match the Polish conditions.
Fieldwork focussed on sections outside built-up areas, i.e. on national roads of the total length of app. 3,000 km. The data were inventoried separately for the left and right edge of the road and for the central reservation. Potential roadside hazards were identified (e.g. trees, slopes, utility poles, engineering structures) as well as the type of cross-section and existing types of safety barriers (concrete, steel, wire rope). Using the data collected, models of road safety measures were developed. By combining the effect of the roadside and safety measures, the models will help to build tools for road network management at the operational level (concrete locations on the road network) and select the right types of restraint systems and design the clearance zone.

road restrain system; roadside; road safety; models