The informational impacts of congestion tolls upon route traffic demands

In this paper, we try to formulate the network equilibrium models with state-dependent congestion tolls under an uncertain environment to investigate the impact of information precision levels of state-dependent congestion tolls upon the drivers' welfare levels. The impacts of two alternative state-dependent congestion tolls schemes, i.e. ex ante tolls and ex post tolls, upon the drivers' route choice behaviors are analyzed. It is shown that total welfare level of drivers surely improve by the introduction state-dependent congestion tolls system with advance information even though traffic information may include some noises in designating network conditions. It is also proven that the perfect information systems with ex post tolls maximize the drivers' welfare among the proposed congestion toll schemes. The paper concludes by illustrating some numerical examples.