Estimation of Arterial Traffic Flow Fundamental Diagrams Using Data from Advance Loop Detectors

Traffic in arterial networks behaves differently from freeways due to the impact of signal control. A lot of efforts have been devoted to the derivation of traffic flow fundamental diagrams on freeways or macroscopic fundamental diagrams of urban networks. However, few of them are focused on individual arterial road link. In this study, the authors introduce a general approach to estimate arterial traffic flow fundamental diagrams using data from advance detectors. Under the assumption of platoon arrivals with no dispersion, the authors derive a trapezoidal fundamental diagram for arterial road links, the breakpoints of which are determined by a set of parameters including saturation flow rate, saturation speed, green ratio, and detector and vehicle lengths. The authors analytically prove that the estimation of queuing time at advance detectors is accurate under minor platoon dispersion. The authors also graphically demonstrate that the impact of initial queues can be ignored under near-stationary traffic conditions, but poor coordination level will drift the observations to the right with higher occupancies. Using data from three intersections along Huntington Dr in the City of Arcadia, CA, the authors show that measurements from advance detectors are more reliable and the flow-occupancy relation is clearer. In order to get the trapezoidal fundamental diagram, the authors estimate the saturation flow rate from a calibration dataset with one year data, and find that it varies a lot among intersection approaches and signal control plans. Furthermore, the authors estimate the upper bounds of flow-occupancy plots using a validation dataset with six month data, and calculate the corresponding Mean Absolute Percentage Errors against with the estimated trapezoidal fundamental diagrams. The validation results demonstrate that the estimated trapezoidal fundamental diagram generally matches the field data well. Overall, research findings from this study provide valuable insights to researchers and engineers to better understand traffic behaviors at signalized intersections and develop more efficient and effective signal control strategies.

• Supplemental Notes:
  • This paper was sponsored by TRB committee ABJ35 Standing Committee on Highway Traffic Monitoring.
• Corporate Authors:

  Transportation Research Board

  ,    
• Authors:
  • Gan, Qijian
  • Petryk, Suzanne
• Conference:
  • Transportation Research Board 98th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2019-1-13 to 2019-1-17
• Date: 2019

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References;
• Pagination: 6p

Subject/Index Terms

• TRT Terms: Arterial highways; Loop detectors; Real time information; Traffic congestion; Traffic flow; Traffic signal control systems
• Candidate Terms: Transportation sensor systems
• Geographic Terms: Arcadia (California)
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 01697765
• Record Type: Publication
• Report/Paper Numbers: 19-05240
• Files: TRIS, TRB, ATRI
• Created Date: Mar 1 2019 3:51PM