ASSESSMENT OF TRAFFIC CONGESTION AND ITS IMPACT ON ROAD CAPACITY IN URBAN AREAS UNDER MIXED TRAFFIC CONDITIONS USING MULTIPLE REGRESSION ANALYSIS - A CASE STUDY IN ADDIS ABABA CITY

Traffic congestion is a complex phenomenon, which is connected to a number of vehicle movements on the road. The major reasons behind this problem are due to various continuous activities in the urban areas such as education, employment, recreation, business, political, social and cultural. These activities in addition to floating and migration increase congestion on city roads. This will affect the traffic stream characteristics and reduces the road capacity and level of service. The present study is aimed to evaluate and analyze the traffic congestion and its effect on road capacity and level of service at  Mebrat haile  mid-block location in Addis Ababa city. To achieve the objective, the Mebrat haile mid-block was divided into four segments appropriately and the traffic volume and speed studies were conducted at each segment, for a period of 10 hours in a day at every 15 minutes consecutive interval. The necessary traffic data including road geometry at each segment was recorded. The congestion levels at each segment were then measured by estimating the reduced speed  between each segment. The volume to capacity ratio (v/c ratio) was then estimated and found to be exceeding 1 in most of the hours of the day, resulting  poor level of service F. Various Multiple Regression Models were developed correlating the reduced speed with traffic volume, composition and road geometry. The results from the analysis indicates that the  traffic congestion on the urban roads, have an impact on urban characteristics.