  In this paper we address the problem of dynamic pricing for toll lanes on
freeways. The proposed toll mechanism is broken up into two parts: (1) the
supply side feedback control that computes the desired split ratios for the
incoming traffic flows between the general purpose and the toll lanes; and (2)
the demand side price setting algorithm that aims to enforce the computed split
ratios.
  The split ratio controller is designed and tested in the context of the
link-node Cell Transmission Model with the modified node model of in/out flow
distribution. The equilibrium structure of this traffic model is presented; and
the case, in which the existence of a toll lane is meaningful, is discussed.
  For the price setting, two alternative approaches are presented. The first
one is commonly used, and it relies on the known Value of Time (VoT)
distribution. Its shortcoming, however, is in the difficulty of the VoT
distribution estimation. The second approach employs the auction mechanism,
where travelers make bids on places in the toll lane. The advantage of this
approach is that it enables direct control over how many vehicles will be
allowed into the toll lane.
