ASSESS IMPACTS AND BENEFITS OF TRAFFIC SIGNAL PRIORITY FOR BUSES

Bus transportation has traditionally served as the backbone of public transportation. Despite the importance and efficiency of buses, compared to the automobile, these vehicles are weighted equally with automobiles at traffic signals where a bus carrying 50 passengers is treated the same as an auto with a single person. Delays caused by traffic signals and by street traffic congestion increase bus operating costs and degrade transit service quality. One approach to minimizing delays to bus transportation is by implementing bus signal priority. Bus signal priority is an attempt to minimize or eliminate delays to buses at signalized intersections by temporarily altering the traffic signal phase so that an approaching bus receives a green phase when it arrives. The potential savings in bus travel times can allow buses to maintain their schedules and provide better reliability in travel times. Although signal priority has proven to be an effective tool for reducing delays to buses, this technique is not always beneficial to the overall traffic network. Providing priority for transit vehicles along a corridor with a large number of transit vehicles can cause a coordinated network to be out of step resulting in an overall increase in delay. Bus signal priority also has the disadvantage of penalizing the cross-street traffic when high transit volumes exist at the corridor. The objectives of the research described in this report are to assess the impacts of and the implementation issues associated with the use of bus signal priority in New Jersey and to assess the benefits and costs of signal priority.