Concept of Stream Equivalency Factor for Heterogeneous Traffic on Urban Arterial Roads
Publication: Journal of Transportation Engineering
Volume 139, Issue 11
Abstract
Mixed traffic flow is often converted to equivalent flow in passenger car units (PCUs) by multiplying the number of each category of vehicles in the traffic stream by their respective PCU factors and then adding them up. PCU is a complex parameter and depends on multitude of factors. This paper presents a methodology to convert a mixed traffic stream into a homogeneous equivalent without making use of PCU factors. Traffic volume and speed data collected on different six-lane urban arterial roads in India are analyzed to determine PCU values of five different categories of vehicles found on these roads. These PCU values are used to convert heterogeneous traffic volume in vehicles per hour to homogeneous volume in PCU per hour. A new term stream equivalency factor (SEF) is introduced in this study and denoted by . It is the ratio of traffic volume in PCU per hour and volume in vehicles per hour. The factor is related to traffic composition and volume on a road through the regression analysis method. A microsimulation program is used to generate the traffic flow data for two, three, four, and five categories of vehicles in the traffic stream, and these data were utilized to present a generalized solution for determining the value of for any combination of traffic composition and volume on a road. The proposed method is simple to use and expected to eliminate the problem of estimation of PCU factors required in many studies.
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Information & Authors
Information
Published In
Journal of Transportation Engineering
Volume 139 • Issue 11 • November 2013
Pages: 1117 - 1123
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Dec 27, 2012
Accepted: May 22, 2013
Published online: May 24, 2013
Discussion open until: Oct 24, 2013
Published in print: Nov 1, 2013
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