Washington State is about to complete a five-year effort to improve the environmental-permitting process for transportation projects. From its start in 2001, the Transportation Permit Efficiency and Accountability Committee (TPEAC) sought to streamline the environmental-permitting process for transportation projects in Washington State. Some of the goals of TPEAC are to reduce mitigation cost, increase environmental benefit, reduce the redesign of transportation projects, and reduce time required to obtain permits. Passage of the Transportation Streamlining Act by the Washington State Legislature in 2001 began the work of this committee. TPEAC has provided a valuable forum to bring together representatives of all entities involved in transportation permitting. TPEAC participants recognize the relationship between their individual roles and the importance of working together to bring about a more streamlined and integrated permitting process in order to use public resources more efficiently and achieve better environmental results. Several technical subcommittees established by TPEAC have developed some important transportationstreamlining tools and policies that help reduce costs and increase environmental benefits. TPEAC’s work to improve Washington State’s transportation permitting process serves as a model for collaborative, multi-stakeholder efforts to increase regulatory efficiency while maintaining high environmental standards.