A THESIS SUBMITTED TO THE FACULTY OF CIVIL ENGINEERING, INSTITUTE OF TECHNOLOGY, SCHOOL OF GRADUATE STUDIES, ARBA MINCH UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN CIVIL ENGINEERING (ROAD AND TRANSPORT ENGINEERING

Abstract

The growing economic and urbanization activities in Addis Ababa have resulted in different types of transportation problems in the city. Problems due to roadside activities are among the most prevalent issues observed in most business areas in the city road network. This mainly arises from inefficient urban planning and traffic management measures taken on the road. As a result of this problem, the operational characteristics of the road as well as the road users are continuously affected. Considering the impact of Road Side Friction (RSF) elements, several studies have been undertaken at the local level. However, these studies were commonly based on methodologies that evaluate the impact of individual friction elements rather than considering the various types simultaneously. Therefore, the aim of this study is to develop mathematical models that are used to represent the various types of roadside friction elements simultaneously further to evaluate their impact on traffic speed based on data collected at selected road segments in Addis Ababa city. The study mainly adopted the videography technique and field measurements to collect all relevant data pertinent to the study. As a part of the analysis, the study adopted a relative importance analysis and regression models in addition to the various statistical tests and evaluations. The result of the study showed that the characteristics of the traffic stream in the study road segment were combinedly represented by a logarithmic function of speed and density with an R2 value of 71.36%. The result of the relative importance analysis also showed that double taxi stop, taxi stop, pedestrian, double bus stop with bus stop and on-street parked vehicle simultaneously accounted for the relative importance of 86.0%. The result again showed that these elements account for the majority of relative importance in a weighted FRIC measure. In line,the traffic speed is relatively affected by these roadside friction elements from high to low, respectively. Similarly, the impacts of RSF on traffic speed are also represented by a linear model with an adjusted R2 value of 83.0%. Furthermore, the result of sensitivity analysis based on the regression model showed that traffic volume, FRIC, PD, and PCS are 1.76%, -7.53%, -16.34%, and 8.04% sensitive to average traffic speed. Finally, it can be concluded that the various RSF elements have a significant impact on the average speed of the traffic stream. Therefore, the result of the study can be practically informative to understand the extent of the problem and implement efficient measures on the road