Simulation of turning traffic at a controlled inter-section

Abstract

Problem. Optimizing the parameters of traffic light regulation can reduce delays and queues of vehicles, increase the throughput of intersections, and thus increase the quality of the functioning of the city's transport network. This question is especially relevant for Ukraine, because in these conditions it is impossible to carry out a significant modernization of the city's transport network, but within the framework of the post-war reconstruction of the city, it is possible to carry out the improvement of the geometric parameters of the intersection. However, among all the factors that affect the throughput of a regulated intersection, in the scientific literature and normative documents, insufficient attention is paid to the geometrical parameters of the intersection itself. Goal. The geometric parameters of the intersection first of all affect the characteristics of the movement of the selected rotating streams, and through this - the saturation of the stream. Therefore, it is of interest to simulate the movement of turning traffic at an intersection and compare the results with empirical models. Methodology. To estimate the permeability of the selected turning lanes, the correction of the ideal saturation flow is most often used with coefficients, the values ​​of which are either calculated depending on the geometric parameters of the intersection (for example, F. Webster's methodology), or are taken as constant (Posіbnik НСМ 2000). The flow saturation value for the selected turning lane was also calculated taking into account the minimum safe distance of the vehicles in the traffic flow. It is shown that these methods give different values ​​of flow saturation. Results. To check the degree of influence of the rotary flow traffic radius on the flow saturation of the selected traffic, simulation modeling of the robot of the conditional adjustable intersection was carried out in the program PTV VISSIM. The parameters of the model were chosen in such a way that a sufficiently long queue was released before the stop line. In the process of imitation, after turning on the green signal, the virtual detector fixed the number of cars that passed through the dedicated right-turn lane. Practical value. The results showed that for selected turning lanes, the saturation flow increases with an increase in the radius of the turning flow trajectory, which corresponds to the classical formula of F. Webster, when the radius value is up to 15 m. Therefore, adjusting the saturation flow for selected turning flows is appropriate this time. When the flow moves along a path with a larger radius, the saturation flow does not depend on the geometry of the intersection.