SPEED-FLOW ANALYSIS FOR INTERRUPTED OVERSATURATED TRAFFIC FLOW WITH HETEROGENEOUS STRUCTURE FOR URBAN ROADS

Abstract

Speed-flow functions have been developed by several transportation experts to predict accurately the speed of urban road network. HCM Speed-Flow Curve, BPR Curve, MTC Speed- Flow Curve, Akcelik Speed-Flow Curve are some extraordinary efforts to define the shape of speed-flow curve. However, the complexity of driver's behaviour, interactions among different type of vehicles, lateral clearance, co-relation of driver's psychology with vehicular characteristics and interdependence of various variables of traffic has led to continuous development and refinement of speed-flow curves. The problem gets more tedious in case of urban roads with heterogeneous traffic, oversaturated flow and signalized network (which includes some un- signalized intersections as well). This paper presents speed-flow analysis for urban roads with interrupted flow comprising of heterogeneous traffic. Model has been developed for heterogeneous traffic under constraints of roadway geometry, vehicle characteristics, driving behaviour and traffic controls. The model developed in this paper shall predict speed, delay, average queue and maximum queue estimates for urban roads and quantify congestion for oversaturated condition. The investigation details oversaturated portion of flow in particular.