A New Model for Level of Service of Freeway Merge, Diverge, and Weaving Segments

In most of the existing highway capacity manuals, level of service (LOS) of freeway weaving segments and ramp junctions is traditionally defined by the speed, volume or density in critical areas of merge, diverge and weaving manoeuvres. In that traditional concept several capacity values of different critical areas (merge, diverge, weaving) as well as upstream and downstream basic freeway segments within the influence areas are evaluated separately. In this paper, a new model which considers the total segment of freeway merge, diverge, and weaving as an entire object is introduced. A combined volume-to-capacity ratio is used for defining the LOS of the total segment. According to the probability and queuing theory, the volume-to-capacity ratio of the whole segment can be considered as a combination of volume-to-capacity ratios in the different critical areas under consideration. The parameters of the new model can be calibrated with field data. Those parameters are functions of the number of lanes on the freeways, the number of lanes in the on-ramps or off-ramps, the length of the acceleration, deceleration, or weaving sections. Varying the model parameters the function can be fitted to the existing capacity models for different types of weaving segments or ramp junctions. With this model, the traffic quality (LOS) can be obtained directly as a function of the volumes on the freeway and on the on-ramp or off-ramp respectively. The new model has the following advantages: a) a uniform function for all types of freeway weaving segments and ramp junctions, b) traffic quality assessment for all critical areas under investigation in one step, and c) easy calibration. The new model will be incorporated into the new edition of the German Highway Capacity Manual (HBS 201X).

• Record URL:
  • http://ac.els-cdn.com/S1877042811009840/1-s2.0-S1877042811009840-main.pdf?_tid=a225ae00884cc3aa78c47f3fc49d55a3&acdnat=1334082378_40b3a889eefedfce88066c22cfbf9578
• Summary URL:
  • http://www.sciencedirect.com/science/article/pii/S1877042811009840
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/18770428
• Supplemental Notes:
  • Abstract reprinted with permission from Elsevier.
• Authors:
  • Wu, Ning
  • Lemke, Kerstin
• Conference:
  • 6th International Symposium on Highway Capacity and Quality of Service
  • Location: Stockholm , Sweden
  • Date: 2011-6-28 to 2011-7-3
• Publication Date: 2011

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References;
• Pagination: pp 151-161
• Monograph Title: 6th International Symposium on Highway Capacity and Quality of Service
• Serial:
  • Procedia - Social and Behavioral Sciences
  • Volume: 16
  • Publisher: Elsevier
  • ISSN: 1877-0428
  • Serial URL: http://www.sciencedirect.com/science/journal/18770428/53
• Publication flags:

  Open Access (libre)

Subject/Index Terms

• TRT Terms: Highway capacity; Level of service; Merging area; Ramps; Traffic models; Weaving sections
• Geographic Terms: Germany
• Subject Areas: Highways; Operations and Traffic Management; I73: Traffic Control;

Filing Info

• Accession Number: 01367674
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 11 2012 11:11AM