PARALLEL SOLUTION OF A TRAFFIC FLOW SIMULATION PROBLEM

Computational Fluid Dynamics (CFD) methods for solving traffic flow co ntinuum models have been studied and efficiently implemented in traffi c simulation codes in the past. This is the first time that such metho ds are studied from the point of view of parallel computing. We studie d and implemented an implicit numerical method for solving the high-or der flow conservation traffic model on parallel computers. Implicit me thods allow much larger time-step than explicit methods, for the same accuracy. However, at each time-step a nonlinear system must be solved . We used the Newton method coupled with a linear iterative method (Or thomin). We accelerated the convergence of Orthomin with parallel inco mplete LU factorization preconditionings. We ran simulation tests with real traffic data from an 12-mile freeway section (in Minnesota) on t he nCUBE2 parallel computer. These tests gave the same accuracy as pas t tests, which were performed on one-processor computers, and the over all execution time was significantly reduced.