Browsing by Author "Ermias, Tesfaye (Mr.)"

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    Road Traffic Congestion Analysis and Traffic Flow Modeling at Meskel Square Signalized Control Intersections
    (Addis Ababa University, 2017-06) Gebremichael, Gebremedhn; Ermias, Tesfaye (Mr.); Fitsum, Getachew (Mr.) Co-Advisor
    Transportation systems are essential to economic and the security of the nations. The effectiveness of a transportation system depends on its ability to support the reliable movement of people, goods, and vehicles from one place to another. An urban traffic system is an important yet complex transportation system composed of vehicles, pedestrians, traffic lights, and a traffic network structure. Problems related to urban traffic is increasingly important, and many researchers are trying hard to solve them. The huge number of vehicles causes serious problems like for example traffic congestion/jams, air and noise pollution, stress to drivers, and fuel and energy consumption. Traffic congestion at intersections, the main focus of this research, is one of many serious global transportation problems of both developed and developing countries for many years and it always exerts a negative externality upon the society. In Africa, vehicle traffic congestion is a new phenomenon with its economic cost on the productivity of the cities' communities. Despite the lower car ownership levels and the intensive road network expansion in Addis Ababa, traffic congestion at intersections has become a serious problem in the day to day activities, specifically, during morning and evening peak hours. The overall goal of this research work is to analyze road traffic congestion and to develop traffic flow model that describes the current as well as the future traffic flows at Meskel Square signalized control intersections. To achieve this objective, an extensive literature review and collection of primary and secondary data related to traffic congestion were conducted. The secondary data were collected by volume counting using a stopwatch for 12 successive days (i.e. 3 hours in the morning, 2 hours in the midday and 3 hours in the evening) for each intersection. Using these data, first effective analysis and discussion was made and then, a simulation model using Arena 14.00 version software was developed. The model were tested and validated under ten scenarios using the secondary data collected by choosing only one intersection. The finding of the study shows that, traffic flow at Meskel Square intersection. The finding of the study shows that, traffic flow at Meskel Square intersections is outlying comparing to the Highway Capacity Manual (HCM) requirements. This is not due to the low capacity of the road only but also due to poor traffic signal phase controlling systems in the corridor. As per the analysis result shows, the Level of Service (LOS) of both intersections lays on “F” value in the morning and evening peak times based on the Highway Capacity Manual (HCM) standards. This shows there is high traffic congestion and flow delay at Meskel Square intersections in the peak hours. After various scenario analysis is tested on the signal time controlling phase, the level of service shifts from “F” to “D” in almost all approaches. At the end of this paper the developed arena simulation model was running for 10 different scenarios time policy. The simulation result shows, the waiting times was decreasing from scenario to scenario and the number of vehicles served at the green phase increases. Even though the queuing lengths were comparable in all scenario simulation results, but it displays a minimum value in scenario 3 taken as the optimal time control policy. These values are (162 seconds red, 75 seconds green) to Meskel Street, (169 seconds red, 68 seconds green) to Bambis street, (142 seconds red, 95 seconds green) to Dembel Street and (178 seconds red, 59 seconds green) to Betemengist Street. At this scenario the queue length per entity across each street reaches minimum value.