Optimal Feedback Control for a Perimeter Traffic Flow at an Urban Region

Traffic flow control has motivated many researchers since early decades of the 19th century. Recently, the concept of a perimeter traffic control for an urban region has been strengthened by a series of works, which have shown that a perimeter controller, located at a region border, can manipulate the transfer flows across the border to maximize the total outflow of the region. The macroscopic fundamental diagram (MFD), that relates average flow with accumulation, is used to model the traffic flow dynamics in the region. Assuming that the control inputs of the cross-border flows are coupled, i.e. the border is always utilized over time for transferring flows by one of the two directions (from and towards the region), and that the urban region has two traffic flow demands generated inside the region with internal and external destinations, and a generated traffic flow outside the region with a destination to the region, the explicit formulation of the optimal feedback control policy and a proof of optimality are provided. The proof is based on the modified Krotov-Bellman sufficient conditions of optimality, where the upper and lower bounds of state variables are calculated.