AN APPROXIMATE ANALYSIS OF THE HYDRODYNAMIC THEORY ON TRAFFIC FLOW AND A FORMULATION OF A TRAFFIC SIMULATION MODEL

An approximative analysis is introduced to the hydrodynamic theory. For an analysis of traffic phenomena in the time-distance space, waves which have continuous property over the space are approximated by some discrete dislocations (referred to as quasi shock waves), the behavior of which is similar to that of shock waves. The graphic construction, successive computation of the queue tail trajectory and a procedure are presented. The results from the approximative analysis are compared with those from direct application of the hydrodynamic theory. Principal conclusions of the analysis are: the traffic phenomena derived from the approximative analysis comes closer to that from the direct application of the hydrodynamic theory as the number of quasi shock waves is increased. In practice, however, sufficient accuracy can be obtained if two quasi shock waves are assigned to represent the waves for each under-and over-saturated region. On the basis of these analytical results, a simulation model was developed for traffic flow on a signalized network. The model was applied to a corridor with a network of 118 links and 44 signalized intersections. The model can well describe the actual traffic phenomena, especially those during periods of heavy traffic congestion. (Author/TRRL)