Simulation of pedestrian-vehicle interactions at roundabouts

The goal of this research is to improve the understanding of and quantify the interactions between pedestrians and vehicles in the vicinity of single lane roundabouts. The work is partly motivated by recent rulings by the U.S. Access Board regarding the potential signalization of all roundabouts in the U.S. to provide "equal access" to blind and low vision pedestrians at such locations. It also motivated by a lack of in-depth analyses in the general area of micro-scale pedestrian-vehicle interactions.; To achieve this goal, the research objectives focused on the development of data extraction and simulation tools. Data extraction enables the specification of the interactions by means of collecting micros-scale, high resolution spatial data to characterize how drivers and pedestrians interact with other drivers and pedestrians near roundabouts. The tool, developed from first principles by the author, is an automated video image processing system (called ITRE-mv) that is capable of detecting and tracking motorized vehicles (in 3 classes) and individual pedestrians in the field of view at any pre-specified time resolution.; The empirical data generated by ITRE-mv were used to calibrate, validate and extend an existing commercial traffic simulation model (VISSIM). The focus of that activity was on analyzing pedestrian and vehicles gap acceptance and driver yielding behavior, which could be incorporated into a microscopic traffic simulation model. The simulation model was successfully calibrated and validated at two sites in North Carolina, using ITRE-mv generated data as the basis.; The simulation model was then extended to analyze and predict the effect of policy and technological treatments on the operational effectiveness of both vehicular and pedestrian traffic. It was found that while a policy that unequivocally provides right of way priority to pedestrians is very effective from an operational perspective, it is quite difficult to implement in practice. On the other hand, technology-based solutions that can inform blind and low vision pedestrians of impending driver yields and presence of crossable gaps could be equally effective, without unduly causing additional traffic delays to motorists as traditional traffic signals are likely to incur.