| This dissertation concerns the development of macroscopic freeway traffic models that are computationally efficient and suitable for use in real-time traffic monitoring and control applications. A primary consideration is the design of parameter calibration methodologies that are automatable and require low computational effort. Toward the fulfillment of these objectives, a macroscopic traffic model, the Modified Cell Transmission Model (MCTM), which is based on Daganzo's Cell Transmission Model (CTM), is presented. Main differences with the basic CTM are that the MCTM uses cell densities as state variables instead of cell occupancies, and accepts nonuniform cell lengths, thus allowing greater flexibility in partitioning freeways. The MCTM has been piecewise-linearized to produce the Switching-Mode Model (SMM), a hybrid system that switches among different sets of linear difference equations depending on mainline boundary data and the congestion status of the cells.; An approximately 14-mile section of Interstate 210 West in southern California was selected for testing the accuracy of these models, and is described along with the data processing methods. Traffic data sources were the Performance Measurement System (PeMS), and a set of manually-counted ramp volumes provided by Caltrans District 7.; The observability and controllability properties of the SMM modes have been determined. Both the SMM and MCTM have been simulated over a 2-mile section of I-210W, using several days of loop detector data. Simulation results show that both models produce density estimates that are similar to one another and in good agreement with measured densities. The mean percentage error averaged over all the test days was approximately 13% for both models.; A semi-automated method was developed for calibrating the MCTM parameters. A least-squares data fitting approach was applied to loop detector data to determine free-flow speeds, congestion-wave speeds, and jam densities for specified subsections of a free-way. Bottleneck capacities were estimated from measured mainline and on-ramp flows. The calibration method was tested on the 14-mile I-210W section, and the calibrated MCTM was able to reproduce observed bottleneck locations and the general behavior of traffic congestion, yielding approximately 2% average error in predicted total travel time. |
