A Proposal for the Estimation of Loss Time of Right-Turn Traffic at Signalized Intersections in Japan

In the planning stage, loss time with the change of phases at signalized intersections is simply determined by the length of intergreen interval in the existing method in Japan. In addition, the drivers completing right turns (comparable to left-turns in the United Sates) during the effective red portion of intergreen interval are roughly considered to be 1~3 vehicles per cycle, dependent upon phase switching pattern and intersection scale. To better account for the unique features of signal phasing and driving behavior of right-turners in Japan, this paper proposes a new method particularly for the estimation of loss time of right-turn traffic. Start-up and clearance loss times under three conventional phasing plans, protected-only right-turn, permissive-only right-turn, and permissive-and-protected right-turn, were first theoretically analyzed, based on time-space diagram and shock-wave theory. Then, field data collected at 7 intersections was used for validation. Results showed that the existing method in Japan tends to provide improper estimation, and the proposed method is however capable of offering good accuracy. Finally, a series of case studies were conducted to demonstrate the application of the new method. Conclusions supported that the new method can more sophisticatedly assess loss time in terms of the length of waiting area and bring short cycle lengths when demand ratio is between 0.65 and 0.80. Also, it is able to simplify signal timing procedure to certain extent by eliminating an iterative check of discharge flow rate of right-turn traffic and cycle length.

Language

  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 22p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01152324
  • Record Type: Publication
  • Report/Paper Numbers: 10-0776
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 10:22AM