Assessing the Effect of Light Rail Transit in Travel Corridor Congestion (A Case Study on Addis Ababa, Ethiopia North-South Corridor)

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Date

2019-10

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Addis Ababa University

Abstract

Transportation plays a vital role in almost all cities around the world because it provides access for people to employment, education, entertainment, health care, and other services. As developing capital city, the urbanization rate in Addis Ababa is increasing rapidly, which in turn increase’s daily commuters, which leads to the necessity of alternative mode of transport, so currently light rail transit has been implemented and found to be effective. Indeed, Light Rail Transit is an effective solution to deal with this problem. Light Rail Systems can be found in a variety of land use context and can operate under a different type of right of way. However, there is an exceptional possibility for vehicle congestion which is traveling along the corridor. The vehicles in this corridor are experiencing additional delays and travel time where there is at grade intersections and pedestrian crossings. The primary objective of this thesis is to assess the effect of light rail transit on travel corridor congestion using a microscopic simulation model called VISSIM. Microscopic traffic simulation models have been playing an essential role in the evaluation of alternatives. To achieve high fidelity and credibility for the simulation model, calibration and validation of the model are the most important. This research presents a calibration and validation of the model by adjusting the car following behavior. The first car following behavior input parameters adjusted is average standstill distance, additive part of standstill distance, and multiplicative part of standstill distance. The validity of the calibration model was also checked through error checking and statistical comparison, it was found that the performance measures obtained by the simulation model were representative of the field condition. The result between the modeled values showed no discrepancy between the model simulation and field measure of performances. The overall result indicates that the reduction of heavy vehicles, on-street parking restriction in the study area has a significant effect on the performance-related measures against traffic (delay, capacity, queue length, and the number of stops) and emission (CO, NOx, VOC) and fuel use. According to Dunnett’s multiple comparison test introductions, an active transit signal priority (ATSP) controller is found to be effective in improving performance measures.

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Keywords

Light Rail Transit, Calibration, Validation, Simulation Model and Active Transit Signal Priority, capacity, delay, queue length, number of stops

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