System optimum, stochastic user equilibrium, and optimal link tolls

Previous studies have shown that the Wardropian system optimum may not necessarily be supported as a (logit-based) stochastic user equilibrium (SUE) by finite and meaningful link tolls. This paper demonstrates that the classical principle of marginal-cost pricing is still applicable in a network under SUE from the standpoint of economic benefit maximization within the context of the classical consumer behavior theory. The marginal-cost link tolls are shown to be meaningful from both economic and behavioral viewpoints, and therefore proposed to be a good alternative to drive an SUE flow pattern toward system optimum.