THE FUNDAMENTAL DIAGRAM, A MACROSCOPIC MODEL FOR TRAFFIC FLOWS

A literature review is presented of the fundamental diagram, i.e. The relationship in a steady-state traffic flow between two of the three variables: volume, density and mean speed. The fundamental diagram is defined and its importance for road design and traffic quality is explained. In addition, applications are given as well as the theoretical and empirical state of the art. Of the research aspects measurement, methods and analysis are discussed. (A) /TRRL/