According to the EPA, 28% of all 2011 GHGs for the US are from transportation related sources1. These are the second largest sources of GHGs in the US after electricity. The US is also the second highest CO2 emitter after China2. These emissions are primarily from burning fossil fuels for transportation usage. While vehicles have become more environmentally friendly with lower emissions, there has still been a steady rise in GHGs from these modes of transportation. The EPA estimates that there has been an increase of ~18% since 1990 for transportation related GHGs, which is most likely due to more vehicles on the road!