Greenhouse gas emissions derived from transportation sources in Tacoma account for the vast majority of all such emissions (72 percent in 2005).  Even among Tacoma municipal emission sources, employee commute emissions outstripped other sources such as fleet vehicles, energy for buildings, energy for streetlights, and water and sewage processing in 2005.  The Transportation Subcommittee of the Tacoma Green Ribbon Climate Action Task Force is considering more than fifty candidate strategies to reduce greenhouse gas emissions from transportation sources through the reduction of vehicle miles traveled, the reduction of single-occupancy vehicle use, the adoption of emissions reduction technologies, and the design of land use and planning strategies.  All candidate strategies can be classified into the list of "solutions" to transportation emissions in the column to the right.  Each solution is associated with  a unique combination of factors including: greenhouse gas reduction potential, cost, affected stakeholders, as well as barriers and benefits associated with implementation.