MACROSCOPIC FREEWAY MODEL FOR DENSE TRAFFIC - STOP-START WAVES AND INCIDENT DETECTION
A continuum model for freeway traffic flow is described which includes relaxation of the equilibrium speed of the static speed-density relation ("fundamental diagram") and anticipation of traffic conditions downstream. Stability analysis shows that in light traffic the equilibrium solution given by the fundamental diagram is stable, while in dense traffic, jams with stop-start waves occur. The formation of stop-start waves is in full analogy to the creation of roll waves in inclined open channels with a suitable water height. The methods to derive such roll wave solutions from the basic hydrodynamic equations of shallow water theory are used to describe the stop-start waves in the freeway model. As in fluid dynamics, where the change from laminar flow to turbulent flow is announced by critical fluctuations, the change from steady traffic to traffic with jams and stop-start waves is indicated by large fluctuations. From theory and measurement of the broadening of the speed distribution due to the critical fluctuations an algorithm of traffic classification and incident detection is derived. On the basis of a simplified version of this algorithm using only local measurements of the speed distribution an automatic traffic jam warning system is developed. (Author/TRRL)
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/isbn/9067640085
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Supplemental Notes:
- Papers presented during the Ninth International Symposium on Transportation and Traffic Theory held in Delft the Netherlands, 11-13 July 1984.
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Corporate Authors:
VNU Science Pres BV
P.O. Box 2073
Utrecht, Netherlands -
Authors:
- KUEHNE, R D
- Conference:
- Publication Date: 1984
Media Info
- Features: Figures; Photos; References;
- Pagination: p. 21-42
Subject/Index Terms
- TRT Terms: Automatic control; Automation; Conferences; Detection and identification; Detectors; Equilibrium (Mechanics); Freeways; Highway traffic; Mathematical models; Speed; Traffic; Traffic congestion; Traffic density; Traffic flow; Traffic incidents; Traffic simulation; Warning systems
- Uncontrolled Terms: Incidents
- Old TRIS Terms: Freeway traffic; Stop-start waves /traffic/
- ITRD Terms: 3882: Automatic; 8525: Conference; 632: Congestion (traffic); 9115: Detection; 7145: Equilibrium; 6473: Mathematical model; 2752: Motorway; 5408: Speed; 755: Traffic; 673: Traffic concentration; 671: Traffic flow; 9113: Warning
- Subject Areas: Highways; Operations and Traffic Management; I71: Traffic Theory;
Filing Info
- Accession Number: 00392076
- Record Type: Publication
- Source Agency: Institute for Road Safety Research, SWOV
- ISBN: 90-6764-008-5
- Files: ITRD, TRIS
- Created Date: Apr 29 1985 12:00AM