Influence on Vehicle Speed Profiles of Interactions with Other Road Users
K F M Aronsson, K L Bång, Royal Institute of Technology, SE
Vehicle speed is influenced by street design and interactions with other road users. Data was collected in field, driving simulator and micro simulation. Pedestrians, buses at bus stops and on-coming traffic had significant impact on speed profiles.
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?) 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 of a pedestrian approach 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 significant impacts 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 traffic simulation model which was calibrated to represent the speed profile changes caused by interactions with other road users and events as described above. The model was then applied for production of speed patterns and speed flow relationships for a range of different street designs, traffic environments and traffic flow. The resulting models are aimed for use in guidelines to assist planners and traffic engineers with selection and evaluation of alternative street designs and traffic management measures.
Association for European Transport