An empirical analysis on the arterial fundamental diagram
For uninterrupted traffic flow, it is well-known that the fundamental diagram (FD) describes the relationship between traffic flow and density under steady state. For interrupted traffic flow on a signalized road, it has been recognized that the arterial fundamental diagram (AFD) is significantly affected by signal operations. But little research up to date has discussed in detail how signal operations impact the AFD. In this paper, based upon empirical observations from high-resolution event-based traffic signal data collected from a major arterial in the Twin Cities area, the authors study the impacts of g/C ratio, signal coordination, and turning movements on the cycle-based AFD, which describes the relationship between traffic flow and occupancy in a signal cycle. By microscopically investigating individual vehicle trajectories from event-based data, the authors demonstrate that not only g/C ratio constrains the capacity of a signalized approach, poor signal coordination and turning movements from upstream intersections also have significant impact on the capacity. The authors show that an arterial link may not be congested even with high occupancy values. Such high values could result from queue build-up during red light that occupies the detector, i.e. the Queue-Over-Detector (QOD) phenomenon discussed in this paper. More importantly, by removing the impact of QOD, a stable form of AFD is revealed, and one can use that to identify three different regimes including under-saturation, saturation, and over-saturation with queue spillovers. The authors believe the stable form of AFD is of great importance for traffic signal control because of its ability to identify traffic states on a signal link.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/01912615
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Supplemental Notes:
- Abstract reprinted with permission from Elsevier.
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Authors:
- Wu, Xinkai
- Liu, Henry X
- Geroliminis, Nikolas
- Publication Date: 2011-1
Language
- English
Media Info
- Media Type: Print
- Features: Bibliography; Figures;
- Pagination: pp 255-266
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Serial:
- Transportation Research Part B: Methodological
- Volume: 45
- Issue Number: 1
- Publisher: Elsevier
- ISSN: 0191-2615
- Serial URL: http://www.sciencedirect.com/science/journal/01912615
Subject/Index Terms
- TRT Terms: Arterial highways; Empirical methods; Interrupted flow; Network links; Signalization; Signalized intersections; Traffic congestion; Traffic density; Traffic flow; Traffic queuing; Traffic signal control systems; Traffic signal cycle; Traffic signals; Uninterrupted flow; Vehicle detectors
- Uncontrolled Terms: Fundamental diagram; Steady state theory (Traffic flow); Turning movements
- Geographic Terms: Twin Cities Metropolitan Area (Minnesota)
- Subject Areas: Highways; Operations and Traffic Management; Planning and Forecasting;
Filing Info
- Accession Number: 01323879
- Record Type: Publication
- Files: TRIS, ATRI
- Created Date: Dec 28 2010 1:30PM