In this thesis, we investigate the problem of optimising the transportation network for AVs both from a theoretical and from a practical perspective. In the first part, we investigate the properties of adding paths to a network and we prove that path additions to transport networks, where AVs are routed, are not supermodular in travel time, extending the seminal result of Braess’ paradox. In the second part, we formulate two network design problems for self-interested AVs. We present the problem of optimising transport networks via path additions and a novel problem design where self-interested users are guided towards optimal paths through the reduction of road capacities. Through capacity reductions, we achieve significant total travel time improvements on six real-world transport networks: Anaheim (USA), Barcelona (Spain), Chicago (USA), Eastern Massachusetts (USA), Sioux Falls (USA), and Winnipeg (Canada). For instance, we improve the Chicago network by up to 7%, saving more than 487 hours of total travel time per traffic hour.
