A simplified pedestrians-vehicles interaction model at road crossings based on discrete events system

Road accident reports show that a large part of accidents involves pedestrians, the category of road users generally considered "weak" with respect to other mobility users, and occurs at pedestrian crossings. It is therefore essential to provide traffic engineers with simulation tools able to forecast the response of a given design solution and compare it with other alternatives. In this paper a simplified and logic model to simulate interaction between pedestrians and vehicles’ drivers at road crossings is presented. The model the crossing process has been represented as a Discrete Events System and allows to estimate the mutual interactions by considering basic and easy to collect parameters. Pedestrian behavior has been characterized in the decision phase considering a gap acceptance criterion, based on parameters derived from probabilistic distribution to take into account the heterogeneity of the pedestrian population. Interaction between pedestrians during the crossing phase is also taken into account considering a cellular model of the crossing area. The model allows estimating safety benefits for pedestrians, and crossing level of service both under pedestrians and vehicular flows points of view, starting from site geometry and field measurements of flows parameters of pedestrians and vehicles In order to check the performance of the model it has been applied to a real site case study. Then the effects of implementation of traffic-calming intervention are also simulated and evaluated.