Title：Leaving the Tub: the Nature and Dynamics of Hypercongestion in a Bathtub Model with a Restricted Downstream Exit
Presenter: Doctor Bao Yue
Time: 2019.11.04 10:00-12:00
Invited by: Prof. Tian Qiong
Location:A716
Abstract:The macroscopic fundamental diagram shows that hypercongestion can occur implying that a lower equilibrium travel time could be obtained at the same flow level. The bathtub model investigates how hypercongestion in urban areas arises when drivers can choose their departure times and routes optimally. This paper investigates equilibrium outcomes and user costs under the realistic assumption that there is limited capacity to exit the bathtub. When the exit capacity of the bathtub is lower than the equilibrium exit flow from the bathtub, no additional inefficiencies arise due to hypercongestion, whereas when the exit capacity is higher than the equilibrium exit flows from the bathtub inefficiencies do occur. The implication of this result is that with a restricted downstream capacity regulating hypercongestion may not be necessary because time gains in the bathtub are lost in the queue at the exit.
