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Title: Microscopic and Macroscopic Approaches to Delay Estimation with Oversaturated Conditions
Accession Number: 01099139
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: Chapter 16 of the 2000 "Highway Capacity Manual" (HCM) contains a widely recognized and well-accepted procedure for calculating per-vehicle control delay at signalized intersections. Appendix F of that chapter discusses the relationship between various components of control delay using cumulative arrival and departure curves. The delay obtained from these curves has certain limitations that need to be recognized if proper conclusions are to be drawn. To illustrate these limitations, a comparison is made between the delay obtained from cumulative curves and the delay obtained through a detailed analysis of vehicle trajectories. A comparison of the control delay obtained from trajectory analysis and that obtained from cumulative arrival–departure curves shows that the cumulative curves omit certain valid portions of the control delay, while including other portions of time that are not delay at all. Taking a macroscopic approach to oversaturated delay estimation, the HCM procedures for dealing with oversaturated conditions are described and their shortcomings are explored using an example of a multiperiod analysis of an oversaturated approach to a signal. It is demonstrated that the current HCM equations can overestimate multiperiod delay and that the assumption of a capacity that is constant from cycle to cycle can underestimate delay at high values of the volume-to-capacity ratio.
Monograph Title: Monograph Accession #: 01118256
Language: English
Authors: Buckholz, Jeffrey WilliamCourage, Kenneth GPagination: pp 52-62
Publication Date: 2008
ISBN: 9780309113465
Media Type: Print
Features: Figures
(9)
; References
(3)
TRT Terms: Identifier Terms: Uncontrolled Terms: Subject Areas: Highways; Operations and Traffic Management; I73: Traffic Control
Files: TRIS, TRB, ATRI
Created Date: Jan 29 2008 3:38PM
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