Uncertainty in Multicommodity Routing Networks: When Does It Help?

We study the equilibrium behavior in a multicommodity selfish routing game with uncertain users, where each user over- or underestimates their congestion costs by a multiplicative factor. Surprisingly, we find that uncertainties in different directions have qualitatively distinct impacts on equilibria. Namely, contrary to the usual notion that uncertainty increases inefficiencies, network congestion decreases when users overestimate their costs. On the other hand, underestimation of costs leads to increased congestion. We apply these results to urban transportation networks, where drivers have different estimates about the cost of congestion. In light of the dynamic pricing policies aimed at tackling congestion, our results indicate that users' perception of these prices can significantly impact the policy's efficacy, and “caution in the face of uncertainty” leads to favorable network conditions.