Social learning in nonatomic routing games

• Published in: Games and economic behavior Vol. 132; pp. 221 - 233
• Main Authors: Macault, Emilien, Scarsini, Marco, Tomala, Tristan
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-03-2022
• Subjects: Incomplete information; Routing games; Series-parallel network; Social learning; Wardrop equilibrium; Routing games; Series-parallel network; Social learning; Incomplete information; C73; D83; C72; Wardrop equilibrium
• ISSN: 0899-8256; 1090-2473
• DOI: 10.1016/j.geb.2022.01.003

We consider a discrete-time nonatomic routing game with variable demand and uncertain costs. Given a routing network with single origin and destination, the cost function of each edge depends on some uncertain persistent state parameter. At every period, a random traffic demand is routed through the network according to a Wardrop equilibrium. The realized costs are publicly observed and the public Bayesian belief about the state parameter is updated. We say that there is strong learning when beliefs converge to the truth and weak learning when the equilibrium flow converges to the complete-information flow. We characterize the networks for which learning occurs. We prove that these networks have a series-parallel structure and provide a counterexample to show that learning may fail in non-series-parallel networks.