Analysis of Gap Acceptance, Capacity and Level of service at Unsignalised ‘T’ Intersection under Mixed Traffic Condition

Abstract

The analysis of gap acceptance, capacity and level of service at uncontrolled unsignalised intersection is very important in developing countries like India. In developed countries such as USA, these intersections are controlled by using stop sign because their existed individual lanes for different class of vehicles and uniform traffic conditions. But in India, this was totally different due to all type of vehicles are using same lane which is considered as mixed traffic condition. Under this condition, each driver’s behavior is different while taking decision to maneuver the intersection safely. Generally, signals are installing instead of stop signs at these intersections because, day to day the traffic is increasing continuously and there are no rules and regulation followed by different drivers to avoid accidents and conflict movements. Installing such signals at every unsignalised intersection is very expensive. So, before installing signals it is necessary to analyze these intersections to know the present service of roads. For the present study two uncontrolled unsignalised intersections at Peerzadiguda X road and Chengicherla X road both NH-163 were selected because, these two intersections are tackled more congestion as increasing daily traffic. The video graphic survey was carried out to estimate the gap/lag, arrival rate, approaching vehicle types, waiting time etc.. Based on this data, further parameters like critical gap, follow-up times, capacity and level of service were estimated accurately using different field techniques like Modified Raff’s method, Harder Method, Greenshield method and Clearing time method etc..which were old and latest methods and also used HCM 2010 as a reference manual. Finally, the results were compared at these intersections to give further solutions like improving of intersection, installing signals, extent of roads, providing medians, providing stop sign etc. to provide better service for future trends.