6 - Traffic Flow Models

Abstract

This chapter introduces the fundamental ideas of traffic modeling as they are applied in the engineering of traffic systems. It describes macroscopic models that predict the average variables of traffic density and traffic flow rates because they are very important for calculating the capacity of roads and highways. Traffic flow, in mathematics and civil engineering, is the study of interactions between vehicles, drivers, and infrastructure with the aim of understanding and developing an optimal road network with efficient movement of traffic and minimal traffic congestion problems. The macroscopic modeling of traffic assumes a sufficiently large number of cars in a lane or on a road such that each stream of autos can be treated as fluid flowing in a tube or stream. On the other hand, microscopic models predict how speed varies with driver sensitivities and responses to various traffic stimuli because they provide a basis for obtaining the gross traffic density and flow rates needed in macroscopic models. These models are being increasingly used to investigate the control of individual vehicles, as well as lines (or lanes) of vehicles.