An integrated route assignment and traffic simulation system with massively parallel computing architecture

This research presents an integrated system for applications in Advanced Traveler Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS) environment. With ATIS-ATMS, the traffic controller has the ability to provide real-time traffic and offer route guidance instructions to ATIS-equipped vehicles. The anticipated benefits will depend on the complex interactions among various factors, including the market penetration rate of ATIS-equipped vehicles, driver behavior and compliance rate, level of congestion, dynamic nature of traffic patterns, and signal control strategies. The proposed system, which has been developed to address these critical issues, consists of two components: route assignment and traffic simulation.; The traffic network simulation component has incorporated three key features essential for ATIS-ATMS operations: (1) the capability of simulating both freeways and surface street networks as an integrated network; (2) a path-processing capability for representing drivers' route choice behavior at an individual/vehicle level; and (3) the capability of simulating different subnetworks at different levels of detail. Three simulation methodologies are integrated into the traffic simulation component. They are macroparticle traffic simulation model (MPSM), modified MPSM (M-MPSM), and microscopic (MICRO) model. The route assignment component follows an integrated assignment-simulation framework which assigns both guided and unguided vehicles to the network dynamically in both spatial and temporal dimensions. It uses a learning process in which the new route assignment uses information gained from previous iteration in computation of new paths. During each iteration, guided vehicles follow routes according to time-dependent shortest paths while unguided vehicles follow static shortest paths.; In order to satisfy the real-time computational requirements, the proposed system has been developed on the Connection Machine, CM-2, a massively parallel computer. Its implementation on the CM-2 is aimed to exploit the parallel nature of the problem and to take advantage of the underlying computing architecture. Extensive numerical examples have been carried out to analyze the computation and application aspects. The research results indicate that (1) parallel computing architectures offer promising platforms for real-time operations and (2) the proposed system is capable of analyzing the network performance under various ATMS scenarios.