An Empirical Analysis of Critical Headway for Drivers Turning Right-On-Red at Signalized Intersections

Right-turn-on-red (RTOR) movements can significantly affect the capacity of right-turn lanes at signalized intersections. Vehicles turning right-on-red must wait for an adequate opening in conflicting vehicle traffic (and/or pedestrian traffic if present) in order to complete the turn and, consequently, there exists a RTOR critical headway. The Highway Capacity Manual (HCM) recommends field measurements of RTOR vehicles in calculating capacity at signalized intersections, but this is not always possible. In these cases, the RTOR must either be assumed to be zero, which may lead to significantly inflated right-turn delay calculations, or estimated based on intersection geometry and traffic patterns. Previous research on the effects of RTOR on capacity and delay has assumed a RTOR critical headway equal to that of the HCM base critical headway values for two-way stop-controlled (TWSC) intersection minor street right turns. To assess this assumption, an empirical analysis of the critical headway for RTOR maneuvers was conducted using observational data obtained from five signalized intersection approaches in different regions of the United States. Headway acceptance and rejection data were extracted manually from high-definition videos taken at the intersection approaches and the RTOR critical headway was determined. It was found the RTOR critical headway is generally less than the HCM base critical headway values for TWSC intersection minor street right-turns, indicating drivers are more aggressive at traffic signals. Implications of RTOR critical headway on capacity and delay calculations for signalized intersections are discussed.

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• Supplemental Notes:
  • This paper was sponsored by TRB committee AHB40 Highway Capacity and Quality of Service.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Russo, Brendan J
  • Savolainen, Peter T
• 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: 11p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Driver performance; Gap acceptance; Headways; Highway capacity; Right turn on red
• Subject Areas: Highways; Operations and Traffic Management; I72: Traffic and Transport Planning; I73: Traffic Control;

Filing Info

• Accession Number: 01520801
• Record Type: Publication
• Report/Paper Numbers: 14-0051
• Files: PRP, TRIS, TRB, ATRI
• Created Date: Apr 2 2014 9:41AM