Fundamental diagram of traffic flows on urban roads: Local versus whole-link approaches

Fundamental diagrams of traffic flow variables have been quite useful in determining freeway operations quality. However, they are usually not used for that purpose on urban roads. This work is an approach toward utilizing the fundamental diagram on urban roads. On the basis of a host of empirical and simulation work, the first steps toward a routine application of the fundamental diagram are sketched. In addition, two approaches are compared, the first uses a traditional fundamental diagram as measured by loop detectors, and the second uses a wholelink approach relating link-travel-speed with volume. The travel times in particular, contain important information that can be used for traffic management applications.