Saturation Flow Estimation at Signalized Intersections in Developing Countries

Saturation Flow (SF) is a key parameter required in capacity analysis of signalized intersections. It is also an important parameter in design of signal timings. Well-established guidelines such as Highway Capacity Manual (HCM) are available for the estimation of SF in developed countries. Traffic characteristics and driver behavior are significantly different in heterogeneous traffic of developing countries. Thus, it is unwise to follow the procedures adopted in developed countries. Another issue in heterogeneous traffic is about unit of expressing flow. In India, flow is expressed in Passenger Car Unit (PCU) in spite of its many limitations. In this study, we develop easy to use regression models to estimate SF at pre-timed signalized intersections having heterogeneous traffic. Traffic data collected with the help of video camera at seven signalized intersections in Mumbai, India were used for the analysis. Initially we show that PCU calculations are not consistent at selected intersections. We propose expressing SF in vehicles per hour per lane-group. In the latter part, two models are developed: one by treating trucks and light commercial vehicles (LCV) separately, and the other by combining the two classes into one. The input parameters required in the proposed models are easy to obtain from the field. We believe that the models developed in this study can be very useful for researchers and practitioners in India where thumb rules are popularly used to estimate SF.


  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 24p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01046175
  • Record Type: Publication
  • Report/Paper Numbers: 07-1570
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 6:12PM