Implementing Actuated Signal-Controlled Intersection Capacity Analysis with Pedestrians.

For an actuated signalized intersection, pedestrian calls are likely to affect the effective greens serving the vehicle movements, which affect thecapacity and delay of the intersection. However, the current procedure inthe Highway Capacity Manual 2000 for analyzing actuated signalized intersections treats pedestrian crossing and timing statically, either having pedestrian calls at all signal cycles or no pedestrians at all. In reality, pedestrian arrivals are random events with some cycles having more pedestrians than others, while other cycles have no pedestrian call at all. This paper demonstrates that the current procedure can lead to erroneous results in capacity and delay estimations. A model is introduced to overcome theshortcomings in the current procedure. The model takes into account the stochastic nature of pedestrian crossings and their effects. The model computes the probability of having pedestrian call(s) in a cycle, and the corresponding capacities and delays for the traffic movements. An implementation framework was developed to help practitioners conduct capacity analysesusing the model. The model's results on a semi-actuated signal controlledintersection were comparable with the results from the SimTraffic micro-simulation model. Using the proposed model, the effects of pedestrians on intersection capacity and delay were analyzed. Depending on the pedestrian volume and traffic conditions, the current Highway Capacity Manual procedure could produce significant error, especially when the pedestrian volume is low, because it doesn't consider the stochastic nature of pedestrian arrivals.