coming soon

The project DIVVA – "Dynamic facility to increase the traffic flow quality and traffic safety at lane drops on motorways" is based on the results of the feasibility study EVA - "Telematically controlled measures to increase the traffic flow quality at construction sites with lane drops on motorways". In DIVVA a telematic facillity to influence the traffic flow at lane drops on motorways was developed and tested. Variable message signs are controlled by telematic devices depending on the current traffic situation. The most important aspects of DIVVA are the intended influence on lane change and merging behaviour as well as the dynamic control of a flexible speed funnel. Logic control algorithms were developed and suitable steering variables were defined in the first phase of the project. The best signal variants were identified from several possible signal images by means of interactive interviews. The second phase consisted of an on-road test and its evaluation. In case of fast flowing traffic it is favourable that drivers change lane previous to the lane drop, as usual. Under congested conditions the ending lane should be used until its very end. Here drivers should change from the dropped lane and merge alternately. The speed funnel changes dependant to the queuing length and avoids fast cars driving into the congested area. The evaluation of the on-road test shows, that the DIVVA-facility is able to influence the traffic flow positively in the intended way. It increases the capacity of the merging area and improves traffic safety. For a further improvement of these effects some small modification of the facility are suggested. The increased capacity reduces time losses and pollutant emissions. The benefit depends on the size and duration of the congestion. The benefit, which arises from the improvement of traffic safety is difficult to quantify, but principally given. Even without the monetary rating of traffic safety, the result of the cost-benefit-estimation over the expected life-time period of the facility is positive.