본 연구의 묵적은 비용편익분석을 통해 청계천사업의 타당성을 확인하는데 있다. 비용항목은 건설비, 유지관리비, 시간손실비용 등이고, 편익은 고가도로 유지보수비 절약액, 환경개선편익 등이다. 시간손실비용은 도로용량축소에 따른 교통혼잡비용을 계산하고, 이를 시간가치로 환산해 계산되었고, 환경개선편익은 선택모형을 활용하여 시민들의 지불의사액에 의해 계산되었다. 추정결과 교통부문의 사회적 비용은 22년간 할인율 7%를 적용해 현재가치로 환산하면 총 1조 8458.9억원으로 추정되었다. 한편, 편익은 가구당 지불용의액 103,309원을 서울시 전체가구로 환산시 복원후 매년 3562억만큼 발생하고 현재가치화 하면 3조 2,162억에 달하는 것으로 추정되었다. 여기에 청계고가도로의 유지보수 비용 절감분 1000억원을 합하면 청계천복원에 따른 사회적 편익은 총 3조 3,162억원으로 추정된다. 사업의 BC는 1.7965이고 분석기간과 할인율에 따라 1.3257에서 부터 1.9251까지 변화하였다.

In 2003, the Seould government has decided to restore the Cheonggye stream. This policy, however, has been under vehement disputes about its economic feasibility. Using the framework of cost-benefit analysis, this paper compares costs and benefits of the project. It also examines how economic feasibility changes as analysis periods and discount rates change. For analyzing the time delay cost caused by the road capacity reduction, Seoul Congestion Management Model(SECOMM) was used. The environmental benefit expressed by citizen`s willingness-to-pay was estimated using a choice modelling method. The study results reveal that the social costs associated with the Cheonggye Stream restoration, when discounted 7% interest rate for 22 years, would reach up to 1.648 billion dollars. The social costs include project cost, congestion cost, and maintenance cost. Under the same conditions, the social benefit was estimated 2.690 billion dollars. The major benefit components include environmental benefit expressed by the willingness-to-pay for the project and the savings of repair costs of Cheonggye elevated highway. The BC ration of this project was estimated 1.7965, and. when changing the interest rates and analysis periods, they vary from 1.3257 to 1.9251. The results imply that the project will be a very lucrative public project when implemented as promosed.