The design and the operation of tunnels for Federal motorways are regulated in the guidelines for both the Design of Motorways (RAA 2008) and for Equipment and Operation of Road Tunnels (RABT 2006). Included in this outline are the references for the choice of the tunnel cross-sections and for the values of the route survey, as well as the requirements for safety and operational procedures. The aim of this research project was to investigate the tunnel buildings with regard to their road safety. Based on the existing information about the route survey, the tunnel structures were categorized according to their specific features. The categorization of the 41 tunnels investigated was carried out in terms of the following features: number of lanes, the existence of shoulders, entries and exits in tunnels as well as the maximum speed limit allowed. In the next phase, a macroscopic accident analysis was carried out. For this analysis, a few road accident reports which were supplied by police stations were examined. Based on this, the accident parameters of the individual tunnel tubes were investigated. The tunnels investigated included ones with and without junctions. In the macroscopic accident analysis, the accident parameters of all the tunnels investigated were contrasted and compared with those of the outer lanes. Due to the evaluation of the accidents in the tunnels, it was determined that the layout of the shoulders would lead to a reduction of the rate and average cost of accidents. Following this a microscopic accident analysis was completed and the junctions within the tunnel structures were investigated. The analysis of the accident occurrences was carried out separately for each tunnel. Primarily, the characteristics of accidents such as the causes and circumstances of an accident were looked at more closely. Observation of the positions of the entries and exits showed that they have no definite effect on the possibility of an accident occurring; however, as a result of entering or exiting a motorway, a lot of accidents still occur. Therefore, the entrances and exits in tunnels should be avoided when possible. Furthermore, an analysis on the flow of traffic in tunnels was carried out. Due to the analysis carried out, the model from speed-flow-relationships (q-V-relations) was selected for the chosen tunnels and for determining their capacity. (Author/publisher)
Samenvatting