ABSTRACT

Traffic congestion as well as traffic logjam has long been a vital facet of municipal or urban planning but has now become a serious challenge that must be addressed due to the speed increase in the number of vehicles and transportation demand. Intersections are usually considered the most complex locations in the road network and has a very considerable effect on operational performance of road traffic. Traffic signals at intersections have a significant effect on traffic operations. Therefore, the objective of this project is to analyze and set measures for improving the traffic operations at three-legged signalized intersections in urban areas.

The efficiency of a road network can be evaluated with different performance parametersone of which includes the flow of traffic at its intersection. For any given intersection,congestion would be experienced during rush hours particularly within the location. In thisstudy, the congestion at selected three leg intersections in Benin metropolis a commercialtown in the southern part of Nigeria was evaluated. Two different peak hours (morning: 9-10am; evening: 4-5pm) were identified for analysis. The traffic data collected over a periodof one hour was converted to passenger car unit corresponding to the standard conversionfactors as specified in Highway Capacity Manual.

The data were analyzed using SidraIntersection Software within boundaries of three optimization criteria (Flow scale, Designlife, and Sensitivity). The target Level of Service was class D while degree of saturation ofa satisfactory proposed design was expected to be less than 1.0. The result of the threecriteria for morning and evening peak hours were analyzed independently. The optimalselecteddesignforagivenintersectionwasbasedonaveragedelayandqueuedistancewithrespecttoavailabledemandflowandtherankofthelevelofservicefortheintersection. The result indicated that the design life criteria have theoptimal performanceon the three selected intersections. A 92 % average reduction of the total delay in secondswas optimized within the three intersections which accounted for about 63 % savings in the  fuelconsumption in litersper hour under designlifeanalysis criteria.