The objective of this project was to empirically assess psychological effects that work zones on German motorways have on road users. Through expert and user focus groups, interviews on motorway stops, an online survey and a driving simulator study, we were able to draw a comprehensive picture of assumed and experienced issues as well as potential solutions. Especially lane width was found to be a heavy contributor to workload when passing through work zones. This finding was also reflected in the results of the simulator study, in which the width of left lane inside a work zone was manipulated. A narrower lane resulted in a reduction of speed and standard deviation of lane position. However, the reduced lane width was also accompanied by a higher duration of close following. Work zone length appears to be a relevant factor as well. Specific work zone sections that were found to be highly demanding where transition areas and temporary exits, a finding that is supported by accident data. Temporary lane barriers made of concrete were rated highly unfavourable as well. In terms of required information, the information that is already available to drivers seems to be mostly sufficient. The "smiley signs" which indicate the remaining length in a work zone were rated rather positively. Effects on driver behaviour could not be found. The regular information signs that state the purpose, total length (distance) and end (time) of the road works as well as other secondary information seem to have some room for improvement. From a user perspective, shortening work zones and widening lanes would be highly desirable. This desire, however, has to be put in context of practical and road safety considerations. Wider lanes cannot be implemented everywhere, and are also known to be linked to increased speed. Likewise, substituting one long for several shorter work zones leads to increased organisational and financial effort, and also results in more of the critical work zone sections (transition areas). Given these aspects, driver needs, practical implications and especially road safety consequences need to be thoroughly considered before a specific recommendation can be made. (Author/publisher)
Samenvatting