The Influence of Structure in Supply and Demand on the Performance Characteristics of Road Traffic Networks: An exploration of how methodological approaches from network science can be implemented for a transportation research problem

Recently, researchers in the field of Network Science have begun to study how the structural properties of road traffic networks affect their performance characteristics. An understanding of how different structures of network infrastructure and travel demand combine to yield different performance characteristics would be useful because it could help identify how existing road traffic networks could be used more effectively or how structural features, which yield desirable performance characteristics, could be built into the construction of new road traffic networks.
Thus far, however, these studies have been restricted to numerical experiments with synthetic networks that do not provide plausible representations of real road traffic networks. Furthermore, these studies have used a disparate range of parameter settings for supply and demand structure, making it difficult to generalise their findings, and have provided no explanations for their conclusions.
To address these deficiencies, this thesis proposes an investigative framework for studying the effects of structure on the performance characteristics of road traffic networks. This framework comprises an experimental part, which describes how to design and conduct numerical experiments so as to provide useful insights into how performance varies with respect to specific aspects of network structure; and an analytical part, which focuses on developing explanations for patterns uncovered numerically.
This thesis then demonstrates the application of this framework to an investigation of how two performance indicators; the average link Volume-to-Capacity ratio and the Price of Anarchy, vary with respect to four aspects of road traffic network structure. As part of this investigation, a simple model of road network generation is presented that produces spectrums of plausible, synthetic road traffic network ensembles, which vary with respect to specific aspects of structure. Focussing on the variation of the Price of Anarchy with travel demand, this thesis then establishes theory that explains several features of the variation shown numerically.