Evaluation of low cost technique "indirect right turn" to reduce congestion at urbanized signalized intersection in developing countries

Traffic congestion in urban areas is becoming part of our daily life in developed countries, as well as in most of the developing countries. Traditional methodologies to manage congestion are not fulfilling the requirements. Limited financial resources and restricted right of way make this statement truer for developing countries. This paper evaluates low cost "Indirect Right Turn Treatment" to reduce conflicts and congestion at signalized intersections in urban areas. Volume and travel time studies were conducted at three signalized intersections in Islamabad (Capital city of Pakistan), where indirect right turn treatments were applied. Travel time study was done using GPS device. It should be noted that traffic operates on left hand side in Pakistan i.e. right turning movements are signalized. To monitor the traffic flow and driver behavior video recordings were also done on each intersection during the peak hours. Microscopic simulation model (VISSIM) and field travel time runs were used to evaluate before and after scenarios. It is found that at some locations, application of indirect right turn reduce travel time and increase the vehicle output. However, at one intersection the implementation of indirect right turn treatment resulted in increased travel times and reduced vehicle output. This is because of the number of vehicles affected by the closure of intersection are higher and also the movement of vehicles at the u-turns was effected by on-street parking. It was also observed that U-turns provided at all locations are not properly design, which elevates the safety issues.