A Comparative Study of Speed and Flow Measurements Methods as Applied to Four Lane Dual Carriageway Roads

Abstract

Flow-density-speed relationships play an important role in traffic flow modelling and provides basis to illustrate traffic flow behaviour under different traffic conditions. Analyses of this traffic condition critically depends on the collected traffic data. Traffic data collection under mixed traffic conditions is one of the major problems faced by researchers as well as the traffic regulatory authorities. Therefore a comparative study on traffic data measurement techniques has been carried out in this study. The traffic data can be collected using different kinds of techniques. In this study, traffic flow and speed measurements have been collected using a pneumatic tube detector method, video capturing method, moving observer method and manual classified vehicle counting method. By comparing these methods, suitable methods are suggested for application depending on the existing conditions. This study concentrated on traffic data collection along four lane dual carriageway roads and they are William Gopallawa Mawatha (AB42) and Gannoruwa road (B365). Along these roads, study areas have been selected such that traffic flow is uninterrupted. Tube detectors have been installed and data has been analysed using Metrocount software. For other methods data have been analysed manually. The flow measurements and speed measurements graphs have been obtained for each direction in both four lane roads. These graphs have been drawn such that they represent both forced flow conditions and free flow conditions. Comparison has been done suing graphs obtained.