Concept of Stream Equivalency Factor for Heterogeneous Traffic on Urban Arterial Roads

Abstract

AbstractMixed 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 K. It is the ratio of traffic volume in PCU per hour and volume in vehicles per hour. The K factor is related to traffic composition and volume on a road through the regression analysis meth...