Analysis of Capacity Drop at Congestion: A Simulation Study

Congestion may occur due to bottleneck formations that result from a lane drop, near on ramp with significant demand, a collision or other incidents. When analyzing data, it can be observed that flow in a bottleneck just before the onset of congestion is usually higher than the outflow of congestion at that particular bottleneck. This traffic flow phenomenon is known as capacity drop. The majority of past empirical studies confirm the existence of capacity drop phenomenon for highway bottlenecks. However, in the literature there was considerable debate about the reasons of the capacity drop. Nevertheless, it is quite obvious that this capacity drop or flow decrease has a considerable influence when designing traffic control devices. In order to investigate this phenomenon, the concept of capacity drop need to be comprehend vigorously. The objective of this paper is to investigate the capacity drop phenomena at the onset of congestion using microsimulation tool VISSIM. The results of the analysis showed that microscopic model VISSIM can successfully reproduce the capacity drop phenomena by showing a discontinuity in the fundamental flow-density diagram. Further investigation through the use of "Oblique Cumulative Plot" provides a clear presentation of some important traffic features at bottleneck. (A) For the covering abstract of this conference see ITRD record number 201309RT334E.

  • Corporate Authors:


  • Authors:
    • Khondaker, B
  • Conference:
  • Publication Date: 2013


  • English

Media Info

  • Pagination: 12 p.
  • Monograph Title: Calgary 2013 - The Many Faces of Transportation - Technical Compendium

Subject/Index Terms

Filing Info

  • Accession Number: 01494287
  • Record Type: Publication
  • Source Agency: Transportation Association of Canada (TAC)
  • Files: ITRD, TAC
  • Created Date: Sep 24 2013 12:59PM