Work-zones of prolonged durations often require a deviation of traffic onto the lane provided for oncoming traffic. In addition to numerous traffic obstructions this also entails significantly increased accident rate. The goal of this research project is to compare variations of traffic routings in work-zones of prolonged duration including diversions of traffic onto the opposite lane. In this process, the effect of access points and other site-specific features in the segment with traffic in both directions are to be considered. Moreover, the relevance of the segments approaching deviations as well as the deviation itself will be investigated with regard to road safety in work-zones. Transferability and comparability of the results to the segments of bi-directional traffic on oncoming traffic lanes should be proved. In the course the project it became apparent that guide barriers are rarely used for oncoming traffic separation in highway work-zones. Mobile safety barriers seem to be preferred over guide barriers. Therefore, the data collective is not comprehensive enough to be incorporated as initially planned as it does not allow for a statistically viable assessment of the degree of safety given by guide barriers in highway work-zones as separation elements in comparison to mobile safety barriers. With regard to the safety assessment based on the results, the main conclusions can be stated as follows: - Work-zones with a traffic layout 3+1 are safer than work-zones with 4+0 and 4+2, - passengers are injured considerably less severely and suffer deaths less often (in the case of an accident) in work-zones with a traffic layout 3+1 as opposed to a traffic layout 4+0, - furthermore, work-zones with a speed limit of 60 km/h are unsubstantially safer than workzones with a speed limit of 80 km/h. The results of the different investigations have shown that a plain comparison of simple traffic layouts without the consideration of additional parameters (such as lane width or the availability of access points) is not suitable as a means to obtain results of high significance. (Author/publisher)
Abstract