The assignment of trips to a road network for the analysis of equitable transport

The past several years have witnessed a growing interest in sustainable urban transportation and a re-evaluation of the role of the automobile in large urban areas. Traffic congestion, air pollution, greenhouse gas emissions, energy consumption and urban sprawl are all topics that have stimulated the development of various strategies that aim to change the way people travel, especially within cities. At the same time, the issues surrounding the best way to finance major transportation infrastructure are framed in a debate about efficiency versus equity. This thesis proposes to contribute to these discussions by clarifying, to a modest degree, the "problem" of urban automobile travel.;The research described in this dissertation is founded on two already-documented concepts: the totally disaggregate information-based approach to urban transportation simulation and geopolitical equity. Following the precepts of the former, this research uses data contained within the 2003 Montreal travel survey. With regard to the latter, the research subjects are the 15 bridges that connect the island-city of Montreal to the mainland. These infrastructure elements play a vital role in the redistribution, among the dozens of municipalities within the urban region, of people and goods and of the external costs of travel, particularly traffic congestion, air pollution and noise.;The travel survey asked automobile drivers to indicate which major bridge they used over the course of their trip. Their responses were meticulously examined to construct a valid sub-sample of declarations describing bridge usage patterns during the a.m. peak period of a typical average weekday. The final sub-sample contained 8,583 observations. Meanwhile, a model road network of the Greater Montreal Area was constructed. This complete network contained over 100,000 links and 70,000 nodes. The links are categorized by functional class and by jurisdiction (municipal, provincial or federal). Since all the simulations are based on the totally disaggregate approach, there is no zone system, no centroids and no origin-destination matrix.;Two types of models were estimated. The first type -- called the validation model -- assigns each trip in the survey sub-sample to the shortest path containing the declared bridge. The second type -- the simulation models -- attempts to predict the choice of bridge using various heuristics provided by discrete choice theory and by the activity-based modelling platform TRANSIMS. The usefulness and relevance of each of the different models are discussed. All the simulation models correctly reproduce around 75% of the observed bridge choices. Comparisons of the itineraries generated by the validation and simulation models permits a detailed analysis of model prediction errors. The validation model is also used to estimate how the costs and benefits of travel associated with the major bridges are redistributed among different population groups within the Greater Montreal Area.;The results of this work yield several original contributions to the discipline of automobile simulation and to the discussion of equitable financing of road infrastructure. First, this research describes a method for using a confusion matrix to identify and in some cases to correct biases in a model of road facility choice. Second, this research examines in detail the phenomenon of driver indifference toward multiple equivalent alternatives, and distinguishes indifference from other types of model error, specifically deviance and gross error. Third, this project represents one of the first applications of real travel demand data to a state-of-the art disaggregate traffic simulation platform (TRANSIMS). Most users of TRANSIMS must synthesize their travel demand data from aggregate information.;With regard to geopolitical equity, this thesis examines not only the redistribution effects among different municipalities, but also the distorting effects caused by the provision of major transport infrastructure by the superior levels of government. This analysis is made possible by the classification of network links by jurisdiction. In addition, a comparison of the aggregate indicators of consumption and supply by the validation model with those generated by a simulation model revealed only small differences, demonstrating that a simulation model could be applied to evaluate the equity dimension of hypothetical transportation policies. The result of these investigations is the formulation of an equalization mechanism for the realization of parity between the numerous municipalities of the Greater Montreal Area based on their respective consumption and supply patterns. It is proposed that such a system would provide an equitable basis for the financing of major road infrastructure like the major bridges. Finally, this research dissects the notion of the costs of congestion and the use of conventional simulation methods to estimate them. Such an exercise is essential to an enlightened discussion about the costs and benefits of automobile travel.