BUS PRIORITY STRATEGY COMPARISONS AT SIGNALIZED INTERSECTIONS

This research firstly proposes a model to predict bus arrival time based on signal database and image processing sensor. Applying the prediction model to specific scenarios with different bus priority levels, the research makes a comparison among bus priority strategies. These priority strategies include bus signal priority strategy with timing techniques of early green or green extension; bus preemption strategy with exclusive lanes; and bus preemption strategy without exclusive lanes. The comparison's results show that the increases of bus priority level can improve the service level of buses significantly, which can make the bus turn-delays at the intersection reduce by up to 100% compared with that of the normal base case. However, high priority levels for buses may negatively affect non-bus vehicles at the intersection, causing an increase in the turn delay of non-bus vehicles, by up to 94.2% for the preemption strategy with exclusive lanes. The bus priority level not only shapes the specific characteristics of bus trajectory as well as impacts on vehicle travel times in the main and side streets but also figures out the role of bus occupancy in the intersection performance.