A real-time traffic simulation using a communication latency hiding parallelization

This paper implements and analyzes 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 one-step and two-step algorithms) to solve the simulation equations were developed and implemented. Tests with real traffic data collected from the freeway network in the metropolitan area of Minneapolis, MN, were used to validate the accuracy and computation rate of the parallel simulation system (with 256 processors). The execution time for a 24-h traffic-flow simulation over a 15.5-mi freeway, which takes 65.7 min on a typical single-processor computer, took only 88.51 s on the nCUBE2 and only 2.39 s on the CRAY T3E. The two-step algorithm, whose goal is to trade off extra computation for fewer interprocessor communications, was shown to save significantly on the communication time on both parallel computers.