The transportation sector generates enormous amount of environmental emission. This study aims to assess the environmental impact of the environmental emissions in a transportation infrastructure project life cycle. Using the fast track transportation project in China as a case study, the materials used and the energy consumed over the life cycle were converted into environmental emissions. The life cycle of fast track transportation project was divided into three phases including construction, maintenance and repair, and demolition phases. Both qualitative and quantitative method were applied to explore the environmental impact of transportation project. The life cycle assessment (LCA) method was used for the development environmental impact assessment (EIA) model to analyze the contribution of each process in the transportation project life cycle. The empirical results show that the construction phase has the highest environmental impact (62.7%) in the fast track transportation project life cycle, followed by the demolition (35.8%) and maintenance phases (1.7%). Among the materials used in the fast track transportation project, steel has the highest proportion of environmental impact in the construction phase (55.5%). This indicates the enormous environmental impact of the construction phase in fast track transportation project life cycle results from the use of steel material. This study contributes to reducing environmental emissions by revealing the greatest phase of environmental impact and material-source of environmental impact over the life cycle in a transportation infrastructure project.