This study is part of a long-term monitoring and evaluation (M&E) program of the Eastern Indonesia National Road Improvement Project (EINRIP). A longitudinal qualitative social research comprising a baseline study and monitoring studies—which included surveys of local social and economic relations—were respectively carried out before and after the road construction. The objective of the 2018 social qualitative research was to make a long-term assessment of the socioeconomic outcomes and impacts of the improvement of the EINRIP project roads in South Sulawesi and Flores. The main focus of the research was the relationship between road improvements and economic development in the areas served by the road. Particular attention was given to examining differential impacts on different social groupings divided based on livelihoods and gender. This study found that national road improvements by EINRIP have contributed positively to the enhancement of the economic activities which led to increased community income and welfare. The increased accessibility and flow of transportation has increased people's mobility to carry out economic activities. Thus, the community has better access to production inputs to increase the quantity and quality of production, as well as broader market reach to sell their commodities. Other factors are also important although it is difficult to see the contribution of each because they are interconnected. In both locations, the types of livelihoods, changes in commodity prices, private sector investment, government policies and programs, and sociocultural factors defined the economic activities as well as determined the magnitude of benefit of the national road improvement for economic development.