Browsing by Author "Ephrem Bogale"

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    A Comprehensive Through Lane Saturation Flow Rate Model for Signalized Intersection by Considering Illegal Crossing Pedestrian Effect at Selected Intersections in Addis Ababa
    (Addis Ababa University, 2025-06) Ephrem Bogale; Yonas Minalu (PhD)
    One significant element influencing urban traffic performance networks is signalized intersections. It can guarantee safe and efficient traffic flow through the crossings and optimize their capacity. Researchers have been examining signalized junction capacities for a long time. However, the pedestrian effect has not been well studied. Two perspectives are used to analyze the effects of pedestrians: 1) Traffic flow is disrupted by pedestrians; 2) Speed and saturation flow rate are reduced as a result of pedestrian interference. One of the crucial aspects of analyzing the capacity of signalized junctions that is influenced by several circumstances is saturation flow rate. Geometric conditions, traffic conditions, driver conduct, traffic light timing, gradient direction, number of lanes, lane width, volume and kind of turning actions, and pedestrian movement are some of the effective aspects that HCM identifies as determining saturation flow. Walking is a popular form of transportation in Addis Ababa, and people who cross the street when green traffic light is on have an impact on traffic flow. We chose five Addis Ababa signalized crossings to examine how pedestrians affect signal capacity. St. Estifanos, Banko de Roma, Ayer Tena, Jemo Michael, and Saris Abo. Their current functional status, being four-legged, high pedestrian flow, High traffic volume, least interference to entry and exit traffic due to parking activities were the criteria for their selection. Video graphic method was used to gather pedestrian and traffic data from the field. The hours of 8:00 AM to 9:00 AM and 3:00 PM to 4:00 PM were used to gather traffic data. To develop a suitable saturation flow equation for estimating capacity and designing traffic infrastructure for heterogeneous traffic, the heterogeneous traffic must be transformed into homogeneous using a common unit, called the PCU. The dynamic PCUs have been computed in this study, which takes vehicle size and speed into account as key variables for PCU component estimation. The Method adopted in this thesis work o generate a model equation to calculate PCU is Speed-Area method which is developed by Dr. Satish Chandra, according to Chandra’s method (1) This study presents a saturation flow rate analysis of selected Addis Ababa's signalized crossings under mixed traffic situations. In order to collect information on traffic volume and speed on city roads, a video graphic technique was used to determine the saturation flow. The headway which is the amount of time that passes between successive cars crossing the stop line had calculated and then 3600 divided by this headway to get the saturation flow rate. Measurements of saturation flow rates generally show 2.47% - 29.53% lower values than those currently used in the Highway Capacity Manual. The saturation flow rates at the local crossings will be overstated if HCM's suggested value is implemented in study intersections; the presence of pedestrians didn’t show significance in through lane saturation flow rate. A general model for the saturation flow rate analysis should have been created in the spot while we design and maintain an intersection in Addis Ababa.
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    Assessment of Chronic Respiratory Symptoms and Associated Factors among Marble Factory Workers in Addis Ababa, Ethiopia: a Comparative Cross-Sectional Study.
    (Addis Abeba University, 2021-01) Ephrem Bogale; Samson Wakuma
    Background :Marble used in the sculpturing of statute and the construction of buildings and monuments is metamorphic limestone. Persons employed in carving statues from stone and marble rock are exposed to dust containing particles of calcium carbonate and silica. Marble has been commonly used as a building material since ancient times. During the cutting process about 25-30%, the original marble mass is lost in the form of dust which is suspended in the air and then inhaled by the workers. Dust particles that are inhaled are lodged in the lung and cause chronic respiratory diseases. Therefore, the aim of this study was to assess the magnitude of chronic respiratory symptoms in marble factory workers in Addis Ababa, Ethiopia and to compare it with a control group of Awash Wine Factory workers who had low level of dust exposure. Objectives: This study was designed to assess the prevalence of chronic respiratory symptoms and associated factors among marble factory workers in Addis Ababa, Ethiopia. Methods: A comparative cross sectional study was done in Addis Ababa, Ethiopia from 21 October 2020 up to 10 January 2021. The Marble factory, which has a high level of dust exposure, and the Awash Wine Factory, which has a low level of dust exposure, were the subjects of a comparative cross sectional study. The study enlisted 492 participants selected by systematic random sampling method and were interviewed using a modified British Medical Research Council respiratory and American Thoracic Society and National Heart & Lung Institute Division of Lung Disease Respiratory Questionnaire. EPI DATA 3.1 software was used to enter data, and SPSS version 23 was used to analyze it. To determine the relationship between determinant factors and chronic respiratory symptoms, descriptive statistics, bivariate logistic, and multivariate logistic regression analysis were used. Result: The mean ages of the participants in the marble factory were 40.41(SD± 9.1) and the mean age of the control group was 40.46 (SD± 9.6). According to the study, the prevalence of chronic respiratory problems was 42.1 percent in marble manufacturers and 16.2 percent in wine factories. Income below 3000 birr, family history of chronic respiratory symptoms and current smoking habits were variables with bivariate significance but multiple logistic regression analysis showed that age greater than 40, previous respiratory disease confirmed by physician, personal protective equipment, past history of confirmed health problems, service years more than 10 years in the factory, and working hours greater than 48 per week were independent factors that determine the development of chronic respiratory symptoms. Conclusion: The present study concluded that workers in the marble industry had a higher chronic respiratory disease compared to controls. To reduce the impact, it is recommended that the workers should, use proper respiratory protective equipment, reduce exposure hours to dust, check health status for early diagnosis and treatment