Feasibility study on the implementation of exclusive lanes for high occupancy vehicles

Abstract The major road network of Vienna is periodically congested during the peak periods. The objective of this study was, to identify sections, where the conversion of an existing lane into an HOV(high occupancy vehicle)-lane would be practically and advantageous. Maximal traffic volume was determined by data of automatic traffic counters. Degree of occupancy was surveyed by the manual count of 90.000 vehicles occupants. Trip duration was measured by means of following car technique, using GPS (global positioning system). For calculating trip duration an approximation for non-stationary queuing systems was applied. Personalized loss of time, fuel consumption and emission of pollutants where used as indicators for the social cost-benefit-analyses. Increase of traffic volume, increase of occupancy and design of the HOV-lanes were investigated in different variants. It was distinguished between the using of HOV-lanes by cars with two or more (2+) or three or more (3+) occupants. Also the effects of permitting HGVs on HOV-lanes were investigated. Approaches for problems concerning to enforcement and marking were developed. On some of the investigated sections of the major road network of Vienna 2+HOV-lanes provoke large social cost-saving (e.g. on the A2 in the south of Vienna). Especially the reduction of the traffic flow caused by increased car occupancy could create important positive effects. Marketing and a campaign encouraging car pooling is required to improve this effect. Therefore, the implementation of HOV-lanes may not be seen as a local singular measure, but as a part of mobility management and has to be included into a general concept. In this way, it is a very promising measure of traffic engineering.