Berehanu, Abesha (PhD)Samuel, Kifle2020-02-102023-11-112020-02-102023-11-112019-06-03http://etd.aau.edu.et/handle/12345678/20590Ethiopia, located in the Horn of Africa, is largely mountainous in topography. The Ethiopian landform is characterized by great diversity. There are flat-topped plateaus, high and rugged mountains, deep river gorges and rolling plains. Constructing surface road on such greatly undulating topography is so difficult. To traverse such kinds of terrain, there may be a need of consructing a bridge or increasing the route length by changing the route direction and/or excavation to arequired level of grade according to the design standard of ERA or AACRA. Therefore, it is important to search for an equivalent but best alternative solution to traverse such kind of topography. As the economy of the country shows a considerable progress, the road infrastructure plays a great role. Road infrastructures have noticable impact on socio-economic development of the nation. Road projects, particularly tunnel road projects, savings of time for motorists or commuters, accident reduction, user cost saving and reduction of CO2 are often the major benefits. These all benefits have a great impact on the GDP of the country directly or indirectly. Specially, the saved time create two areas of contentions. One is predicting what the time savings would be for the road user; the other is estimating what those times savings are worth to the community and even the countries GDP. Converting these benefits which get off by constructing tunnel road to displace the Entoto mountain, the enumerable out put of Benefit-Cost ratio of 3.07:1, an NPV of 15,674.38 METB and an IRR of 36.0 percent, which shows that the project have a greate impact the county GDP. This implies that the Entoto tunnel road is the best alternative transportation system for areas or the country. In general, even if tunnel roads constitute costly infrastructure in terms of construction cost throughout the world, however, from Ethiopian topography point of view, constructing tunnel road is the feasible and sustainable alternative. The costs of construction of tunnel road project in Ethiopia instead of surface road in mountainous and escarpment terrain is offset by economic benefits of travel time saving, user cost saving, urbanization development in the surrounding areas of the cities and towns of Ethiopia like Addis Ababa, enhancing traffic fluidity along the route, increasing diverted and induced traffic to developed area due to the tunnel project, comfort, safety, reliable routes (mountain crossings) as well as the overall reduction of the environmental impact on the surrounding areas. Therefore, constructing tunnel road in Ethiopia is an effective and efficient alternative transportation infrastructure from its topography point of views.en-UStopographyTunnel roadEthiopian landformERAAACRAThesis