E. K. Nyantakyi, C. A. Adams, J. K. Borkloe and D. Pobee / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 4, Jul-Aug 2013, pp.2566-2590 2566 | P a g e Synchronization of Signalised Intersections: A Case Study of Three Major Intersections on the 24th February Road, Kumasi, Ghana E. K. Nyantakyi 1 , C. A. Adams 2 , J. K. Borkloe 3 and D. Pobee 4 1 Department of Civil Engineering, Kumasi Polytechnic, P.O. Box 854, Kumasi, Ghana 2 Department of Civil Engineering, KNUST, Kumasi, Ghana 3 Department of Civil Engineering, Kumasi Polytechnic, P.O. Box 854, Kumasi, Ghana 4 Department of Civil Engineering, Kumasi Polytechnic, P.O. Box 854, Kumasi, Ghana ABSTRACT Signalized intersections are critical elements of an urban road transportation system and maintaining these control systems at their optimal performance for different demand conditions has been the primary concern of the traffic engineers. Traffic simulation models have been widely used in both transportation operations and traffic analyses because simulation is safer, less expensive, and faster than field implementation and testing. This study evaluated performance of selected signalized intersections using micro simulation models in Synchro/SimTraffic. Traffic, geometric and signal control data including key parameters with the greatest impact on the calibration process were collected on the field. At 5% significant level, the Chi square test and t-test analyses revealed that headway had a strong correlation with saturation flow compared to speed for both field and simulated conditions. It was concluded that changes in phasing plan with geometric improvement would improve upon the selected signalized intersection’s level of service. An interchange therefore should be constructed at Anloga intersection to allow free movement of vehicles thereby minimizing congestion and accident occurrences. Stadium and Amakom signalized intersections should be coordinated to allow as many vehicles as possible to traverse those intersections without any delay. Key words: Performance measures, Sensitivity Analysis, Signalized intersections, Synchro/ Sim Traffic, S I. INTRODUCTION In general, “simulation is defined as dynamic representation of some part of the real world achieved by building a computer model and moving it through time” [1]. Computer models are widely used in traffic and transportation system analysis. The use of computer simulation started when D.L. Gerlough published his dissertation: "Simulation of freeway traffic on a general-purpose discrete variable computer" at the University of California, Los Angeles, in 1955 [2]. From those times, computer simulation has become a widely used tool in transportation engineering with a variety of applications from scientific research to planning, training and demonstration. The 24th February Road is an East-West principal arterial of about 5.4 km length from KNUST junction to the UTC traffic light. The road is a 2-lane dual carriageway, and paved over its entire length. The road provides the main route that leads into the Kumasi metropolis from the southern parts of Ghana. The Anloga, Stadium and Amakom signalized intersections are three major intersections on one of the major arterials of Kumasi. These selected signalized intersection approaches are traversed by the same main arterial road entering Kumasi from Accra. They share similar traffic and driver characteristics. The road corridor is relatively heavily trafficked [3]. The intersections are characterized by long vehicular queues at the approaches of the intersections, especially during morning and evening peak periods of the day. However, for some time now observation of the current traffic situation at the selected intersections shows that very long queues of vehicles form on the intersection legs. Traffic congestion levels continue to rise daily at the selected intersections and there are significant travel time delays and lower levels of service [3]. Previous studies by [3] on the performance of the intersections attributed congestion to critical capacity, intersection controls and abuse to motorists and/or pedestrians. It was concluded that most of the sections on the 24 th February road have their capacities approaching critical (v/c ratio>0.6) and that this contributes in part to the congestion which results in delay and subsequent poor performance of the road. It was therefore recommended that this section of the 24 th February road will be highly critical in the next 3 to 5 years (period from 2004 – 2009). As part of the recommendations [3], the report proposed to improve upon the signalization and capacity at the intersection through; revision of signal timing, phasing plan, lane assignment/designation and inclusion of exclusive NMT phase phase at Anloga Junction, revision of signal timing and phasing plan and inclusion of