Microscopic Theory of Phase Transitions in Freeway Traffic

Abstract

The aim of this chapter is an analysis of phase transitions based on a microscopic three-phase traffic theory. As discussed in Sect. 2.4 and Chap. 10, in empirical observations moving jams do not emerge spontaneously in free flow, i.e., an F→J transition is not observed. Instead of this phase transition, an F→S transition, i.e., the spontaneous emergence of a local region of synchronized flow, is responsible for the onset of congestion in free flow. Only later, and usually at another freeway location can an S→J transition, i.e., moving jam emergence in synchronized flow, occur spontaneously. We will see in this chapter that the microscopic three-phase traffic theory can explain and predict F→S→J transitions observed in real traffic flow.