Operational Impacts of Copenhagen Left as Alternative to Diagonal Left Turns of Bicycles at Signalized Intersections

At signalized intersections, diagonally left-turning bicyclists impede through automobile traffic and may experience significant delay. As an alternative to diagonal left-turns, Copenhagen Left operations can be used, in which left-turning bicyclists are required to go straight along with through automobiles from the same approach, stop, wait for the green interval for the cross street, and then go straight along the cross street to finish the maneuver. The objective of this study was to compare Copenhagen Left with diagonal left-turn maneuver in terms of impacts on capacity of automobile traffic and delay of bicyclists. To this end, an analytical capacity model was developed based on the observed behavioral patterns of automobiles when impeded by diagonally left-turning bicyclists. Micro-simulation models were used to assess delays incurred to bicyclists under both Copenhagen Left and diagonal left-turn operations. Numerical results evidenced that the capacities estimated by the proposed model were consistent with micro-simulation method. While Copenhagen Left enhances capacities of automobiles, it is not universally appropriate for all situations. Copenhagen Left can considerably increase delay for left-turning bicyclists at low-volume, small-sized intersections, which may lead to low compliance rate by bicyclists. A successful implementation of Copenhagen Left does not rely only on proven operational benefits, but also on sufficient storage space for the resulting standing bicyclists, clear pavement striping and signage, and effective education for the traveling public.

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• Supplemental Notes:
  • This paper was sponsored by TRB committee ANF20 Bicycle Transportation.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Chen, Xiaoming
  • Chunfu, Shao
• 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: 17p
• Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Bicycle lanes; Cyclists; Highway capacity; Left turns; Microsimulation; Signalized intersections; Traffic delays
• Subject Areas: Operations and Traffic Management; Pedestrians and Bicyclists; Planning and Forecasting; I72: Traffic and Transport Planning; I73: Traffic Control;

Filing Info

• Accession Number: 01506401
• Record Type: Publication
• Report/Paper Numbers: 14-0548
• Files: PRP, TRIS, TRB, ATRI
• Created Date: Feb 3 2014 9:18AM