Liquid fuel consumption by medium- and heavy-duty vehicles (MHDVs) represents 26 percent of all . liquid transportation fuels consumed and has increased more rapidly—in both absolute and percentage terms—than consumption by other sectors. In early recognition of these trends, which are forecast to continue until 2035 (DOE, EIA, 2009), the Energy Independence and Security Act of 2007 (EISA; Public Law 110-140, Dec. 19, 2007), Section 108, was passed, requiring the . Department of Transportation (DOT), for the first time in history, to establish fuel economy standards for MHDVs. In December 2009 the . Environmental Protection Agency (EPA) formally declared that greenhouse gas (GHG) emissions endanger public health and the environment within the meaning.
