EFFECT OF TURNING-LANE USE ON SATURATION FLOW AT SIGNAL CONTROLLED INTERSECTION

Abstract

In developing countries, the road users do not have a tendency to follow a certain lane discipline pattern. The drivers tend to occupy any position across the road width. This lack of lane discipline together with a wide range of vehicles of various sizes leads to a disordered pattern of traffic both when queuing as well as when discharging. In addition to this, the presence of turning movements at the intersection approaches hinders the movements of the through moving vehicles which further leads to the faulty estimation of the saturation flow rate. Eventually, the efficiency and the level of service of the intersection of the intersection gets affected. In order to accurately estimate the saturation flow, the study of these factors becomes very crucial. This study aims at studying the effect of turning lane use on the saturation flow at signal controlled intersections. Data from four different intersections has been collected and the saturation flow values for both the through and right turning movements have been estimated. Through movements and the right turning movements are the major focus of the study. The change in the saturation flow rate due to change in the proportion of the right turning vehicles in the traffic stream has been discussed in the study. Moreover a saturation flow model is developed by regression technique based on the percentage of - the different vehicle categories in the traffic stream. The model is tested on another intersection and the results are found satisfactory. The effect of different vehicle categories on the saturation - flow have also been brought up in the study.