Demand-Independent Tolls
share
Wardrop equilibria in nonatomic congestion games are in general inefficient as they do not induce an optimal flow that minimizes the total travel time. Tolls can be used to induce an optimum flow in equilibrium. The classical approach to find such tolls is marginal cost pricing. This requires the exact knowledge of the demand on the network. In this paper, we investigate under which conditions tolls exist that are independent of the demand in the network. We call them demand-independent optimum tolls (DIOTs). We show that such tolls exist when the cost functions are shifted monomials. Moreover non-negative DIOTs exist when the network is a directed acyclic multi-graph. Finally, we show that any network with a single origin-destination pair admits DIOTs that, although not necessarily non-negative, satisfy a budget constraint.
READ FULL TEXT