DemandIndependent Optimal Tolls
Abstract
Wardrop equilibria in nonatomic congestion games are in general inefficient as they do not induce an optimal flow that minimizes the total travel time. Network tolls are a prominent and popular way to induce an optimum flow in equilibrium. The classical approach to find such tolls is marginal cost pricing which requires the exact knowledge of the demand on the network. In this paper, we investigate under which conditions demandindependent optimum tolls exist that induce the system optimum flow for any travel demand in the network. We give several characterizations for the existence of such tolls both in terms of the cost structure and the network structure of the game. Specifically we show that demandindependent optimum tolls exist if and only if the edge cost functions are shifted monomials as used by the Bureau of Public Roads. Moreover, nonnegative demandindependent optimum tolls exist when the network is a directed acyclic multigraph. Finally, we show that any network with a single origindestination pair admits demandindependent optimum tolls that, although not necessarily nonnegative, satisfy a budget constraint.
 Publication:

arXiv eprints
 Pub Date:
 August 2017
 arXiv:
 arXiv:1708.02737
 Bibcode:
 2017arXiv170802737C
 Keywords:

 Computer Science  Computer Science and Game Theory;
 91A13;
 91A43
 EPrint:
 18 pages, 5 figures