EFFICIENT TRANSIT PRIORITY AT INTERSECTIONS

On most transit routes, private vehicles and public transit share a common right-of-way. However, their respective operations are very different from one another, causing an adverse interaction, especially when transit vehicles stop to load and unload passengers on-line at signalized intersections. The severity of traffic delays that are caused when transit operations are ignored by traffic signal control models is illustrated. The impacts on traffic flow caused by transit vehicles stopped to load passengers on-line are illustrated in terms of a typical arrival profile at an intersection, including both cars and a streetcar. It is seen that the streetcar loading operation can significantly reduce capacity and cause delay to both transit and private vehicles, especially when the signal optimization does not take this phenomenon into account. It is shown that, by considering transit loading effects when designing signal timings, delays to both transit and private vehicles can be reduced. Fixed- and real-time methods for providing appropriate transit priority to reduce travel times for transit passengers, and sometimes also to private vehicles, are discussed.