Simulation-based dynamic traffic system: A GIS approach.
详细信息
文摘
This research develops a simulation-based dynamic traffic assignment (DTA) model and an integrated GIS application system for the simulation-based DTA. A new approach for the problem of optimal traffic assignment in dynamic networks with multiple origins and destinations is proposed in this dissertation. The objective of the DTA model is to assign the vehicles to the network over time to minimize the total travel time experienced by all the vehicles traveling through the network. The main goal of the simulation-based DTA modeling is the real time simulation of large size networks with detailed turning penalties and restrictions. As a heuristic solution approach, the DTA model adopts a microscopic traffic simulation with route planning. In addition, the traffic network over the time horizon is treated as a discrete-time dynamic system. Moreover, the dynamic network modeling incorporates individual driver behavior and the interactions between vehicles. The travel demands and network performance in this model are represented by a time dependent O-D matrix, link costs, and queuing delays.;The modeling of the simulation-based DTA involves several different traffic modeling techniques that address issues related to vehicle generation, route choice, and vehicle movement. A dynamic vehicle generation model was developed to convert the time-dependent O-D matrix to a dynamic vehicle departure pattern at each centroid. Using a time-dependent shortest path model, vehicles choose and change routes on the way to their destinations according to dynamic traffic conditions. A microscopic traffic simulation model provides an understanding of traffic operations at the level of individual vehicles and detailed network description.;A methodology for implementing the simulation-based DTA model in a GIS environment is presented. This methodology includes building a spatial transportation database with a set of specific data models and integrating the simulation-based DTA model with the GIS (DTA-GIS system). The sophisticated GIS design and related tools provide a flexible and efficient platform for modeling DTA and integration of transportation network data. With the DTA-GIS system, network modification and changes representing various demands scenarios are made in the GIS environment, and the results of model are effectively presented. The development of DTA-GIS system is based on the object-oriented programming technique which is very flexible and allows for easily modifying the models or adding new models.;The application of the simulation-based DTA model is demonstrated in a case study using the street network in City of Lawrence, Kansas. The results from the case study serve to demonstrate its applicability for dynamic traffic assignment and vehicle route guidance.