Substantiating the efficiency of circular traffic use in the context of road network in Dnipro City within software environment PTV VISSIM

Abstract

Currently, arrangement of modern circular intersections of small- and medium-size diameters is among the most efficient methods to improve accident record and prevent incidents right within the crossings. The decreased incident rates within such crossings can be explained by massive reduction of the number of conflict points; geometrical parameters resulting in significant velocity decrement; and the improved pedestrian traffic. The world practices have been analyzed as for the circular traffic implementation; basic components of the circular intersection have been listed; and comparative analysis of the modern circular crossings and classic circular crossings has been performed.
Intersection of Naberezhna Zavodska Street-Pavlov Street intersection in Dnipro City has been selected as a test object within a road network with substantiation of the selection criteria. Traffic intensity at the intersection has been obtained with the help of full-scale observations for morning rush hour (i.e. 7 a.m.-8 a.m.). Software product PTV VISSIM 11 has been applied as the modeling tool. According to the algorithm, proposed by the authors, two traffic simulators of Naberezhna Zavodska Street-Pavlov Street intersection have been developed with control traffic and circular traffic. Qualitative analysis of the modeling results has helped conclude that control traffic factors into major traffic jams. The authors have selected a list involving the seven indices (i.e. average delay time; average stop number; average velocity; average idle time; average period of all the vehicles passed in the traffic jam; maximum length of the jam; and CO emission) for further analysis being the most important to evaluate efficiency of circular traffic implementation. Their absolute values resulting from the modeling as well as calculated relative values have been represented. The modeling results mean that circular traffic is more favourable to improve traffic according to each selected index within the range of 3% - 92%. Value of the proposed complex parameter of the circular traffic efficiency is 1.00; in terms of traffic light – the value is 0.34. Thus, total efficiency of the proposed solutions for the selected object is 66%.
The efficiency indices may be of different importance while making final decision concerning traffic arrangement involving their ranging (or determination of the weight coefficients). In the near future, the authors are going to involve experts, i.e. specialists who are experienced in solving problems as for the traffic arrangement and development of traffic models within VISSIM environment.
Key-words: road network, traffic safety, conflict points, circular crossing, simulation, traffic jam length, average velocity, delay time, PTV VISSIM.