Safe, efficient and user-friendly transportation of people and goods have been a premier point of concern for all the developed and the developing countries around the globe. National Highway N-5 or GT road is the most important highway link in Pakistan. It carries about 80 % of the country freight traffic. When this heavy traffic passes through the twin cities of Rawalpindi and Islamabad, it causes congestion and environmental hazards particularly in business centers of Rawalpindi city. Because of this heavy traffic volume passing through the cities situated along N-5, bypasses to all of them have been provided however, Rawalpindi is the only city along N5 which is still without a bypass. A bypass to Rawalpindi city is, therefore, inevitable. Besides this, the Bypass will also provide a short access to the traffic on the Motorway (M2) destined for the western part of Rawalpindi. For this research work Rawalpindi Bypass is taken as a hypothetical scenario and is evaluated for its benefits. Besides addition to the networks of highways across Pakistan this bypass has many other benefits which include decrease in congestion from Islamabad and Rawalpindi main arteries (ISB Highway and IJP Road) that results in travel time savings, vehicle operating cost savings, safety savings and reduced air pollution. This research aims to produce an engineering and scientific comparison of various costs and benefits associated with the road agency and users about the construction of an alternative. The Project involves transportation demand estimation on different segments of the National and Arterial roads, Project Costs, travel time savings, safety saving, vehicle operating cost savings, economic efficiency analysis, Air quality impact and multi criterion transportation decision making. The transportation decision making process usually involves the evaluation of effectiveness and efficiency of an alternative decision with respect to a base case DO-NOTHING Scenario. Author have taken the existing road way structure with no improvements as DO-NOTHING Scenario, whereas the construction of Rawalpindi Bypass (60 Km) with 2 lanes in each direction is taken as Alternative B and Rawalpindi Bypass (51 Km) as Alternative C. Multi criteria decision making technique is used for decision because of multiple options with different dimensions, both monetary and nonmonetary. Basing of MCDM this study recommends Alternative C (51 Km) for Rawalpindi Bypass.