Teklu, Bikila (PhD)Admasu, Netsanet2018-07-232023-11-112018-07-232023-11-112017-04http://etd.aau.edu.et/handle/12345678/9684For everyday travelers, the frustration of traffic congestion is obvious. Understanding the impact on cities and the economy, however, it is not as straightforward as many would like it to be. From an economic perspective, congestion’s main impact is the lost productivity from more time spent traveling to work rather than working; delaying (or missing) meetings; foregoing interactions among individuals or personal activities due to long travel time; and spending more time to accomplish tasks than would otherwise be necessary if we could reliably plan for accomplishing the same things at free-flow speeds. And also Emissions may increase as vehicles spend more time in congestion, idling or crawling, and undergoing numerous acceleration and deceleration events.by this the environmental cost will be higher. In short, a region’s economy does better when people spend more time working and doing things they find valuable and less time traveling to do them. We depend on our transportation system to provide access to people and places we want to go. Following the economic and population growth in Addis Ababa, traffic congestion problem has emerged and the problem is even growing faster. In this study, the level of the traffic congestion for selected area of Addis Ababa city was quantified using travel time approach. Travel time, traffic volume, and travel speed data were collected at two intersections. Accordingly, the travel rate, the delay rate, total travel delay (veh.-min and per-min), were calculated. And also, the total congestion cost was estimated. The result showed that on average the maximum delay of 826 veh – min and 616 veh. – Min. was lost during the morning and the evening peak period respectively at those approaches. The total cost of congestion for specific approaching distance was above Birr 210,805.87 per year during off peak time and Birr 343,597.99 per year during peak time. And the total loss due to congestion will be above Birr 132,792.12 per year on single selected approach. Key word: - Traffic Congestion, Congestion costs, DelayenTraffic Congestion; Congestion costs; DelayThesis