The governors of nine East Coast states announced Tuesday they are pursuing a wide-ranging and ambitious plan to rein in transportation-related emissions.
Transportation emissions are the nation's largest source of greenhouse gases, just ahead of electricity production, according to the U.S. Environmental Protection Agency.
Connecticut, Delaware, Maryland, Massachusetts, New Jersey, Pennsylvania, Rhode Island, Vermont, Virginia and Washington, D.C. joined the regional collaboration.
California has led the way on emission reductions, passing AB 32 back in 2006, which is paying dividends in the Bay Area even as the economy and population grows in the region.
And just this month California air officials announced they will require the state to have zero emissions buses on the roads by 2040.