This lecture discusses the fundamental diagram (FD) and the relations between the 3 traffic flow variables. The important points in the FD such as empty road, maximum intensity, capacity point and jam point will explained. The influences of circumstances like rain, darkness etc. will be discussed. Furthermore the flow regimes stable/unstable and free flow/congested will be explained with the aid of the FD. Some applications of the FD are discussed. Namely, the levels of service, dynamic/static assignment modeling, and the impacts of driving behaviour (car-following). At last some examples of FD’s that are frequently used are explained. Greenshields model, the FD of Smulders, Schematized model of Daganzo, Wu’s model with capacity drop and the theory of Kerner are covered.

Also read chapter 4 about fundamental diagrams and  appendix C. Gas kinetic modeling in the reader.