An Automatic Calculation Method of Identifying the Hysteresis Loop Characteristics in Macroscopic Fundamental Diagram

Recent studies showed that hysteresis phenomena are exhibited in macroscopic fundamental diagram (MFD) in urban freeway networks. This paper proposes an automatic calculation method of identifying MFD hysteresis loop characteristics and apply it to explore the characteristics of the hysteresis loops and the factors affecting the hysteresis pattern. Compared to the traditional observation method, this automatic calculation method extracts key characteristics of hysteresis loop directly from the network flow-density data. This method improves the efficiency to characterize hysteresis loop by identifying the direction of hysteresis loop, starting point and ending point of the hysteresis loop, and the maximum average network flow. To test this automatic calculation method, the macroscopic fundamental diagram for urban freeway network in Milwaukee is presented in this study. By analyzing the relationship between average network flow and average network density with the loop detector data in Milwaukee freeway network, we find that the MFD of Milwaukee freeway network exhibits clockwise hysteresis loop phenomenon, where higher average network flows are observed during the loading process of congestion, while lower network flows are observed during the offset of congestion with the same average network density. Key characteristics of hysteresis loop are extracted by the automatic calculation method and calculation results are validated by empirical observation data. With the automatic identifying method, deeper investigation is conducted by analyzing the spatial spread of congestion in the network. The results indicate that the spatial distribution of congestion over the network will affect the characteristics of the hysteresis loops.

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

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Jin, Peter J
  • Zhang, Jian
  • Ran, Bin
• 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: 21p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Hysteresis; Network analysis (Planning); Traffic density; Traffic flow theory
• Uncontrolled Terms: Fundamental diagram
• Geographic Terms: Milwaukee (Wisconsin)
• Subject Areas: Data and Information Technology; Highways; Operations and Traffic Management; I71: Traffic Theory; I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 01517589
• Record Type: Publication
• Report/Paper Numbers: 14-2305
• Files: TRIS, TRB, ATRI
• Created Date: Mar 10 2014 9:24AM