Representing the effects of transit stops at signalized intersections

When buses/streetcars stop to load/unload passengers in the travelled right-of-way they delay other traffic. Various methods have been proposed to account for this capacity reduction. The simplest way is to reduce the effective green time by the amount of green time during which the transit vehicle prevents other vehicles from reaching the intersection. This is complicated by the acceleration/deceleration for the stop, and the overlap of green/amber/red phases in a stop. Representing the effects of transit stops in signal network optimization models is particularly critical. The paper identifies the transit stop interaction problem, discusses its implications, and examines methods for estimating the effects of transit stoppings on intersection capacity and representing these in both fixed-time and real-time signal optimization models.