ESTIMATION OF PASSENGER CAR UNITS FOR HETEROGENEOUS TRAFFIC CONDITION USING VEHICULAR SPEED AND COMPOSITION AT MID – BLOCK SECTION

Author(s)

Burma Vamshi Krishna - Department of Civil Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad, Telangana, India -

Adepu Ramesh - Department of Civil Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad, Telangana, India -

Molugaram Kumar - Department of Civil Engineering, University College of Engineering, Osmania University, Hyderabad, Telangana, India -

Abstract

Traffic conditions in India are entirely different from other developed countries of the world. The traffic flow is highly dynamic in nature and observed at all mid – block section and interaction of vehicles is also expected to change with the mix characteristics. It is also observed that the interaction among the vehicles is maximum and highly complex during peak period. In this situation the mixed traffic condition situation different types of vehicles share the same roadway space without any physical segregation. The interaction of vehicles under above situation is expressed as the amount of resistance caused to flow of traffic by a vehicle type when compared with standard vehicle (passenger car). Passenger Car Unit (PCU) which is a suitable measure to represent the relative impedance caused by a vehicle under heterogeneous traffic. PCU depends on vehicular speed, vehicle type, and traffic volume. In this article an attempt is made to develop PCU values for heterogeneous traffic conditions on urban roads. PCU values obtained from the study different category of vehicles is compared with the PCU values provided in IRC recommendations. It is concluded that estimated field PCU values vary with speed, land use pattern and vehicles dimensions. Traffic flow curves when plotted with optimum PCU values show close to ideal fundamental curves, this also improves considerably with the change in roadway characteristics. The curves representing fundamental traffic flow relationships among three basic variables, namely speed, density and flow have also been established. Thus a systematic approach has facilitated to understand the heterogeneity in traffic flow parameters has been made through this investigation.