Modeling Delay During Heavy Traffic for Signalized Intersections with Short Left-Turn Bays
This paper develops theoretical delay models for protected left-turn operations at a pretimed signalized intersection during heavy traffic. When the through traffic demand is heavy, residual queues from the previous cycle may occur and elevate the probability of blockage to the left-turn bay, leading to increased delay for left turns. A probabilistic left-turn delay model based on the queuing diagram is proposed for a leading left-turn operation; the influence of residual queues and blockage by the through traffic are taken into account. When the left-turn demand becomes heavy, the left turns may spill back to block the through traffic, resulting in through traffic delays. Through traffic delay is modeled probabilistically on the basis of the analysis of left-turn bay spillback for a lagging protected left-turn operation. The left-turn delay models are validated through carefully designed simulation studies using VISSIM and the results are compared with those from the Highway Capacity Manual (HCM) delay model, which does not consider blockage or spillback situations. The proposed delay models can be used to replace the uniform delay term in the HCM model for high-demand situations when the left-turn operation is affected by spillback and blockage.
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- Summary URL:
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Availability:
- Find a library where document is available. Order URL: http://www.trb.org/Main/Blurbs/166654.aspx
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Authors:
- Yin, Kai
- Zhang, Yunlong
- Wang, Bruce X
- Publication Date: 2011
Language
- English
Media Info
- Media Type: Print
- Features: Figures; References; Tables;
- Pagination: pp 103-110
- Monograph Title: Highway Capacity and Quality of Service 2011
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Serial:
- Transportation Research Record: Journal of the Transportation Research Board
- Issue Number: 2257
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Exclusive phasing; Left turns; Signalized intersections; Traffic delays; Traffic models; Traffic queuing; Traffic simulation
- Identifier Terms: Highway Capacity Manual; VISSIM (Computer model)
- Uncontrolled Terms: Heavy traffic; Spillback effects (Traffic)
- Subject Areas: Highways; Operations and Traffic Management; I73: Traffic Control;
Filing Info
- Accession Number: 01336710
- Record Type: Publication
- ISBN: 9780309222938
- Report/Paper Numbers: 11-3069
- Files: TRIS, TRB, ATRI
- Created Date: Apr 18 2011 12:24PM