Influence on Vehicle Speed Profiles of Interactions with Other Road Users

Speed profiles for motor vehicles on urban streets are influenced not only by the street design and traffic performance, events such as interactions with pedestrians and cyclists, buses, on-street parking, exits from minor roads etc. (called “side-friction events”) also affect driver behaviour. A bottom-up research methodology was developed and applied including a wide range of stationary and mobile field surveys for study of individual driver behaviour. Controlled experiments in a driver simulator programmed to represent the studied field sites were also carried out. Speed profiles showed good resemblance between simulated and observed behaviour for the event pedestrian approaches a crosswalk. Simulated speed behaviour of drivers passing an occupied bus stop proved that women drove with a lower speed than men did. All in all, the results showed that crossing pedestrians, occupied roadside bus stops and encounters with vehicles in the opposing direction of travel had a significant impact on driver speed choices. In a second stage of the project, the observed driver behaviour including response to the studied side-friction events was used for programming of a microscopic simulation model, which was calibrated to represent speed profile changes caused by interaction with other roads users and events as described above. The model was then applied for production of speed patterns and speed flow relationships for a range off different street designs, traffic environments and traffic flow. The resulting models were aimed for use in guidelines to assist planners and traffic engineers in the selection and evaluation of alternative street designs and traffic management measures. ©Association for European Transport and contributors 2006