A preliminary feasibility study evaluates various aspects of a project such as environmental assessment, field study, technological validity, and economic feasibility. Among them, economic feasibility is the most important factor to use in selecting a road route in Korea. A proper preliminary feasibility study considers all costs incurred in the life cycle of the project, including construction costs, land acquisition costs, collateral expenses, and operation and maintenance costs. However, only construction costs are traditionally considered in the assessment of the financial viability of national road projects. In addition, while 3D modeling techniques have brought improved designs and engineering processes to the construction industries, their application in preliminary feasibility studies remains rare. We have developed a system that employs building information modeling and geographic information systems for estimating the cost of building a national road that can be applied in the preliminary feasibility stage. The proposed system is composed of three modules that estimate construction costs, land acquisition costs, and O&M costs. Based on the road route, the proposed system analyzes cross sections through the topography and subsequently determines the probable road, bridge, and tunnel sections, and their project costs. Overall, the proposed system could assist a reasonable decision making for best route selection and further facilitate improved project delivery.