Delays caused by traffic signals and by street traffic congestion
increase bus-operating costs and degrade transit service quality.
Bus signal priority is an attempt to minimize or eliminate delays
to buses at a signalized intersection 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 its schedule 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.