In recent years, the advantages and disadvantages of the so-called extra-wide highways have been studied. These are considered as a road category with extra-wide lanes (i.e. 5-6.5 m lane width) between two-way highways and motorways so that overtaking is continuously possible. The advantage of these extra-wide highways is seen in better driving comfort especially with respect to choice of speed. Comprehensive measurements of traffic flow situations and an analysis of safety aspects were undertaken on five road sections using induction loops and video observations for data collection. For this purpose a new configuration for the location of induction loops was developed to be able to detect overtaking within the extra-wide lanes. More than 500 traffic accidents on these facilities were analysed. The study was designed to quantify traffic flow and safety criteria in comparison to those on normal two-way highways and motorways. The study showed that extra-wide highways can serve as an alternative to normal two-way highways, because the widening to extra-wide lanes increases the quality of flow and decreases at the same time the accident risk. This road type can therefore be recommended when traffic demand does not require a motorway and when cost and environmental effects are crucial. (A)
Abstract