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Braess's Paradox in an Agent-based Transport Model

Thunig, Theresa; Nagel, Kai

Braess's paradox states that adding a link to the network can increase total travel time in a user equilibrium. In this paper, Braess's paradox is analyzed in the agent-based transport simulation MATSim. It can be observed, that two different types of the paradox occur: In the absence of spill back effects, the delay per agent caused by adding a new link is bounded, i.e. the delay per agent will not increase by extending the time span during which agents depart and, therefore, increasing the number of agents. In the presence of spill back effects, the delay per agent is unbounded. The same holds for the price of anarchy in both cases which gets unbounded if spill back effects are considered. As a consequence, Braess's paradox tends to be underestimated in models that do not capture spill back effects.
Published in: Procedia Computer Science, 10.1016/j.procs.2016.04.190, Elsevier BV