ON THE STABILITY OF VEHICULAR TRAFFIC FLOW--A PHENOMENOLOGICAL VIEWPOINT. IN VEHICULAR TRAFFIC SCIENCE

The aim of this investigation is to explain the scatter of data points obtained when flow of vehicular traffic as a function of concentration is measured. A schematic representation of data and the curve fitted to the data is provided. Normally, such data comes from measurements of single-lane flow in tunnels and multi-lane flow on freeways. The scatter of the data is small for concentrations less than the concentration at maximum flow. For higher concentrations, the flow at first decreases and then breaks up, resulting in wide data scatter in this saturated flow regime. It is this scatter that this paper attempts to explain by showing the instability which exists if the flow-concentration relationship is given by a convex curve resembling the line shown in a graphical figure provided. Analysis results are presented.