The Simulation of Traffic Flow to Obtain Volume Warrants for Intersection Control: Technical Paper

Abstract

The control of vehicular traffic at street intersections has been one of the most studied items in the traffic engineering field, yet much remains unknown. Intersections are the critical element of streets in that their characteristics determine the efficiency and capacity of the entire street system. Here one common area must accommodate the vehicular flow of two streets and the conflicting maneuvers of their several approaches. The purpose of this research was two-fold. The first phase of the study was the development of a model, whereby a traffic intersection could be simulated on a digital electronic computer. The particular intersection chosen for study was a four-legged, right-angled intersection of a high-volume major arterial street with a lower-volume minor arterial street. The major arterial had four lanes with parking prohibited, and the minor arterial had two travel lanes with parking permitted on both sides. Both arterials were operated as two-way streets. The intersection is typical of many intersections located in intermediate urban areas and in suburban areas. The second phase of the study was the operation of the simulated intersection under two appropriate types of traffic control; namely, the two-way stop sign and the semi-traffic-actuated signal. The purpose was to establish a realistic set of volume warrants for the given class of intersection. Such warrants were to indicate when, from the standpoint of delay, it would be advantageous to go from stop sign control to actuated-signal controls The major variables used were the traffic volumes carried by the two streets.