Integrating the Dynamics of Heterogeneity in Aggregated Network Modeling and Control

Real traffic data and simulation analysis reveal that for some urban networks a well-defined Macroscopic Fundamental Diagram (MFD) exists, which provides a unimodal and low-scatter relationship between the network vehicle density and outflow. Recent studies demonstrate that link density heterogeneity plays a significant role in the shape and scatter level of MFD. Evidently, a more homogeneous network in terms of link density can result in higher network outflow, which implies a network performance improvement. In this study, the authors introduce two macroscopic models, region and subregion-based MFDs, that model the density heterogeneity in urban networks in order to anticipate the heterogeneity effect. The dynamics of heterogeneity and how they can affect the accuracy and scatter of a multi-region MFD model are studied. The authors also introduce a boundary/perimeter flow control by integrating the MFD modeling. The perimeter controller operates on the border between two urban regions, and manipulates the percentages of flows that transfer between the two regions such that the network delay is minimized. The optimal perimeter control problem can be solved by a model predictive control approach, where the prediction model is the aggregated region-based MFD and the plant (reality) is formulated by the subregion-based MFDs, which is a more detailed model. The perimeter control alleviates the traffic congestion directly by manipulating the perimeter transfer flows of regions while indirectly tries to maximize the outflow of each region by making the regions more homogeneous. The results of this research can provide an insight on the dynamics of heterogeneity in urban network traffic control.

• Supplemental Notes:
  • This paper was sponsored by TRB committee AHB45-1 Traffic Flow Theory and Characteristics Special Paper Review.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Ramezani, Mohsen
  • Haddad, Jack
  • Geroliminis, Nikolas
• Conference:
  • Transportation Research Board 93rd Annual Meeting
  • Location: Washington DC
  • Date: 2014-1-12 to 2014-1-16
• Date: 2014

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 16p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Macroscopic traffic flow; Network analysis (Planning); Traffic congestion; Traffic density; Traffic models; Urban areas
• Uncontrolled Terms: Fundamental diagram
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management; I71: Traffic Theory;

Filing Info

• Accession Number: 01520118
• Record Type: Publication
• Report/Paper Numbers: 14-0710
• Files: TRIS, TRB, ATRI
• Created Date: Mar 26 2014 10:13AM