Analysis of Traffic Flow Characteristics on Signalized Arterials

The characteristics of traffic flows on signalized arterials are examined within a cellular automata micro-simulation model. The model is used to analyze arterial throughput and travel times for given densities, coordination schemes and signal spacings. A fundamental 3-D relationship between flow, density and offsets for signalized arterials is established. It is shown, in particular, that arterial throughput is dependent on offsets and that the constituent single intersection limiting capacity, as determined by the saturation flow and the green splits, can only be realized under optimal coordination conditions within a limited range of densities on the arterial. This is a manifestation of the important role that signal coordination and, in fact, Intelligent Transportation Systems (ITS) actions in general play in the operation of urban street networks.