Transportation authorities are responsible for managing the stormwater runoff that carries pollutants from the transportation-adjacent land and vehicles. The proper stormwater management approach like green infrastructure can help control flooding and the runoff pollutants that may impair water environment and threaten the ecosystem and human health. Furthermore, green infrastructure that can be applied at different spatial scales and decentralized arrangements, have been adopted and implemented in the transportation infrastructure design. However, such implementation is project-based without analysis at system level or sewer scale. A framework is needed to design and evaluate the integration of green stormwater infrastructure in transportations planning at systems level. The overall goal of the proposed project is to develop a modeling framework integrating hydrological simulation, water quality modeling, life cycle assessment (LCA) and cost analysis (LCCA) that can be used for design and planning for surface transportation with spatial implementation of green infrastructures. The phase III of the project developed a system-level optimization framework to determine the optimal allocation (i.e., location, size, and type) of GSI implementation, completed with the deliverables of a spatial optimization model, and a scenario analysis of runoff, water quality, environmental impacts, and cost of existing and optimized candidate GSI implementation.