Impacts of fuel service stations located at signalized intersections on traffic flows - A case study of Kumasi City (Ghana)

Abstract

The impacts on traffic flows by Fuel Service Stations (FSS) located within 50 m vicinity of four (4) signalized intersections in Kumasi City were assessed. Changes in saturated flow rates, delays and lost times were the im-pact assessment indicators. Reduction in saturation flow rates ranged from low of 2 % to high of 56 %, depend-ing on orientations of the FSS to the intersections. Access to the FSS facilitated circumvention of the  intersecti-ons, thereby easing congestion and delays. At one FSS, there was 7.9 % overall reduction in intersection delays, while in the other 3 FSS, the overall intersection delays were increased by 8 - 30 %. The actual lost times excee-ded the allotted signal operational time of 4 s, thereby  reducing the effective green times. The existing traffic conditions were simulated for optimal traffic flow using Synchro 6.0 plus Sim Trafficware with traffic flow cha-racteristics, signal control data and geometric features of the intersections as inputs to determine the clearance lost times of critical movements. Comparison of outputs of the simulation runs of  existing and control (steady flow states or intersections without FSS)  indicated that if the operational signal timings were optimized to   com-mensurate the actual lost times, the existing situations would experience reduced delays and congestions.