Vehicle miles traveled (VMT) refers to the number of miles traveled by motor vehicles, usually measured per capita and per annum. Combined with initiatives to reduce the carbon content of fuels and to increase vehicle efficiency (see Climate TechBook: Transportation Overview), reducing the overall amount of driving (through carpooling, shifting to other transportation modes, or reducing the need for travel through more compact land development) is a crucial element to reducing greenhouse gas (GHG) emissions from the transportation sector. A number of states have enacted policies to curb the upward climb of VMT, which increased at an average rate of two percent per year from 1990 to 2007, and has only recently plateaued due to the impacts from the economic recession. Several of these policies address GHG emission reductions directly, while other “Smart Growth” plans are designed to incentivize higher-density, compact, and mixed-use development. This type of development reduces the need for travel by putting housing, shopping and businesses within reasonable distances of each other. In many cases of Smart Growth planning, GHG emission reductions are a co-benefit to several other—often primary—goals, such as more convenient and accessible living or reducing sprawl into open spaces and agricultural lands. More recently, Smart Growth plans have designated GHG emission reductions as a primary goal.