Calibration of a Macroscopic Traffic Flow Model with Stochastic Saturation Rates

It is well known that freeway capacity (saturation rate) is highly uncertain and that a nominal value alone may not suffice for traffic management purposes. To analyze the impact of capacity dis- ruptions, the authors consider a macroscopic traffic flow model with stochastic saturation rates, called the stochastic switching cell transmission model (SS-CTM). The SS-CTM enables analysis of traffic delay and throughput drop due to uncertainty of capacity. In this article, the authors present a method for calibration of parameters of the SS-CTM using real traffic data from the Caltrans Performance Measurement System (PeMS). Nominal parameters except saturation rates are estimated using a linear regression-based method. The stochastic saturation rate model is developed by clustering of observed saturation rates (mode identification) and constructing a Markov chain governing the switches between the identified modes. The authors also apply the proposed method to a segment of the US Route 101. The results imply that the saturation rate may deviate from the nominal value for a remarkable fraction of time. In addition, correlation between saturation rates at adjacent locations is significant and is thus relevant for delay and throughput analysis

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

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Jin, Li
  • Amin, Saurabh
• Conference:
  • Transportation Research Board 96th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2017-1-8 to 2017-1-12
• Date: 2017

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References; Tables;
• Pagination: 25p
• Monograph Title: TRB 96th Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Calibration; Highway capacity; Macroscopic traffic flow; Markov chains; Saturation flow; Stochastic processes
• Identifier Terms: California Department of Transportation
• Uncontrolled Terms: Cell transmission model
• Subject Areas: Highways; Operations and Traffic Management; Planning and Forecasting;

Filing Info

• Accession Number: 01628069
• Record Type: Publication
• Report/Paper Numbers: 17-02496
• Files: TRIS, TRB, ATRI
• Created Date: Mar 2 2017 5:04PM