Modeling and Control of Network Macroscopic Fundamental Diagram during Holidays: A Case Study of Qingming Festival in Tianjin

Abstract

In this paper, the macroscopic traffic states and network traffic dynamics during the Qingming Festival holiday are explored with the Macroscopic Fundament Diagram (MFD), including the weekday before the holiday (WBH), the day of Qingming Festival (DQF), and the ordinary weekday (OW). The network is heterogeneous on the densities’ distribution, and the congested areas are different in location and size. Normalized Cut (Ncut) algorithm is used to partition the heterogeneous network into multiple homogeneous subregions. The MFD of each subregion is distributed within the critical density on the WBH, and the high-density region moves from the city center to the periphery. On the DQF, high-density areas are on the central and west of the urban network. The congested branch appears on the MFD of the subregion. Then, two calibrated dynamic models, are applied to analyze the network evolution based on the partitioning results. On the basis of the calibrated model, several control strategies are proposed to relieve regional congestion on holidays. According to the simulation results, congestion on the DQF can be alleviated by controlling the external inflow ratio of subregion 2 or limiting the amount of traffic entering subregion 2 from the outside.