This report summarises and integrates the results of a Field Operational Test (FOT) on lateral support systems. This FOT was initiated by the Transport Research Centre (AVV) in order to understand the impact of Lane Departure Warning Assistant (LDWA). LDWA might contribute to increased traffic safety and reduce incidental congestion resulting from accidents involving heavy vehicles. The development of lateral support systems in general and the FOT in particular should be seen against the background of these two major problem areas: traffic safety and traffic flow and capacity. A consortium of TNO Human Factors, TNO Inro, ITS (Nijmegen University), ARCADIS, University of California at Berkeley (PATH) and the University of Minnesota performed the research of the LDWA FOT. The research was organised in 6 major work packages: analysis of the driving task and the role of lane departure warnings; behavioural effects of LDWA systems; expert opinion on traffic flow effects of lateral driver support systems; acceptance of LDWA systems; infra-structural consequences of LDWA; relation of LDWA with narrow lanes. For each work package the most important conclusions are described and the results with regard to traffic safety and with regard to traffic flow and capacity are integrated. Overall we can conclude that the effects of LDWA on traffic safety could be positive. When all heavy vehicles are involved with LDWA, approximately 10% of the injury accidents in which heavy vehicles are involved on secondary roads and motorways can be prevented maximally. This is equal to approximately 274 injury accidents per year. However, this is the most optimistic LDWA effect. The real effect is probably lower because of a number of reasons. It is for example not expected that in all cases when a warning occurs, the driver can prevent the accident at the moment he is alarmed by the LDWA. With respect to traffic flow LDWA systems as such are not expected to have an influence in either a positive or a negative way. There might be an indirect effect on traffic flow by preventing accidents that would have resulted in congestion. In the most optimistic scenario LDWA might be able to prevent 1.3% of the total congestion time in The Netherlands. Only when LDWA is combined with other technologies, clear positive effects on traffic flow can be foreseen. (Author/publisher)
Abstract