Road Traffic Congestion Analysis and Traffic Flow Modeling at Meskel Square Signalized Control Intersections
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Date
2017-06
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Addis Ababa University
Abstract
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.
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Keywords
Traffic Flow Modeling, Signalized Control Intersections, Road Traffic Congestion