International Journal of
Science and Technology Education Research

  • Abbreviation: Int. J. Sci. Technol. Educ. Res.
  • Language: English
  • ISSN: 2141-6559
  • DOI: 10.5897/IJSTER
  • Start Year: 2010
  • Published Articles: 79

Full Length Research Paper

Estimation of roadway capacity of eight-lane divided urban expressways under heterogeneous traffic through microscopic simulation models

  Errampalli Madhu* and S. Velmurugan
Traffic Engineering and Transportation Planning Area, Central Road Research Institute (CRRI), Mathura Road, CRRI (P.O.), New Delhi - 110020, India.
Email: [email protected]

  •  Accepted: 03 November 2011
  •  Published: 31 December 2011



The aim of this study is to develop a microscopic simulation model by considering eight-lane divided urban expressway. For this purpose, the partially access controlled Delhi - Gurgaon Expressway which handles about 220,000 vehicles/day has been considered. From the collected data, speed - flow equations of different vehicle types on eight-lane divided urban expressways have been developed using PARAMICS simulation software. The developed simulation model has replicated the ground conditions realistically with the mean percentage error in speed ranging about 2 to 15% across all vehicle types considering the heterogeneous traffic mix prevalent on Indian urban roads. The study revealed that the roadway capacity of eight-lane divided urban expressways is about 11,435 passenger car units/hour/direction. Further, the formation of virtual lanes by vehicles (that is, formation of eight virtual lanes in just the one direction of eight-lane divided carriageway) has been extensively examined and its impact on roadway capacity has been estimated. It was observed from this study that the roadway capacity of eight-lane divided urban expressways under no virtual lanes condition (that is, traffic plying on the demarcated four lane in one direction of eight-lane divided carriageway) would obviously reduce the roadway capacity by about 15%. At the same time, it is to be noted that though the imposition of restriction on virtual lanes decreases the average free speeds by 7%, it would enhance the safety situation due to less vehicular interactions.


Key words: Free speed, speed-flow equations, roadway capacity, lane change behaviour, urban expressways.

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