Traffic Management Considering Congestion-Based Flow Reductions

Abstract

The cell transmission model (CTM) is widely used in studying optimal traffic management strategies. Since the CTM does not properly model the effect of congestion on traffic flows, a generalized linear model accounting for congestion-based flow reductions is considered. Therefore, the different linearized frameworks will be studied and discussed with their respective properties, as well as the traffic management tools (TMTs) used by these linear programs to obtain optimal solutions. Out of these five TMTs, three rely on traffic holding which is the result of linearizing the CTM model. Because traffic holding is an undesired phenomenon, we discuss a heuristic that eliminates traffic holding on ordinary links, where traffic holding is most unrealistic. Finally, through two numerical examples, we find that strategies under the (realistic) setting of congestion-based flow reduction (produced using the generalized CTM) can differ greatly from those produced using the CTM framework that predominates in the literature, and that the heuristic proposed is an effective tool that yields realistic optimal solutions.