A Communication Latency Hiding Parallelization of a Traffic Flow Simulation

This work implements and analyses a highway traffic flow simulation based on continuum modeling of traffic dynamics. A traffic-flow simulation was developed and mapped onto a parallel computer architecture. Two algorithms (the 1-step and 2-step algorithms) to solve the simulation equations were developed and implemented. They were then tested on an nCUBE2, a 1024 node hypercube with very slow inter-processor communication (IPC) times. Tests with real traffic data collected from the freeway network in the metropolitan area of Minneapolis, Minnesota were used to validate the accuracy and computation rate of the parallel simulation system. The execution time for a 24-hour traffic-flow simulation over a 15.5-mile freeway, which takes 65.7 minutes on a typical single processor computer, took only 88.51 seconds on the nCUBE2. The 2-step algorithm, whose goal is to trade off extra computation for fewer IPC’s, was shown to save more than 19% on total execution time.