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Department of Energy's Question of the Month



Question of the Month: What are the current and future medium- and heavy-duty vehicle fuel efficiency and greenhouse gas emissions standards?


According to the U.S. Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA), greenhouse gas (GHG) emissions from medium- and heavy-duty vehicles (collectively, HDVs) are expected to surpass light-duty vehicle (LDV) emissions by 2030. The Energy Independence and Security Act of 2007 directed the U.S. Department of Transportation to establish fuel efficiency standards for HDVs. Then, in 2010, President Obama announced a new national program to implement coordinated fuel efficiency and GHG emissions standards for medium- and heavy-duty engines and vehicles. As you may have seen last month, EPA and NHSTA recently finalized the most recent set of requirements under this program.
 First promulgated by EPA and NHTSA in 2011, these coordinated standards are being implemented in two separate phases, beginning with Model Year (MY) 2014 to 2018 (Phase 1, which has now been extended through 2020) and followed by MYs 2021 to 2027 (Phase 2), with some exceptions. Under Phase 1, the GHG emissions and fuel efficiency standards generally increase in stringency in MY 2017, then remain steady through MY 2020. GHG emissions and fuel efficiency standards under Phase 2 of the program increase first in MY 2021, and then again in MYs 2024 and 2027. Although the Phase 2 standards do not begin until MY 2021, manufacturers may need to begin compliance measures beforehand in order to be adequately prepared to meet the targets.
Fuel efficiency and GHG emissions standards are determined differently for each of five regulated heavy-duty (HD) engine and vehicle categories: combination tractors; vocational vehicles; HD engines used in combination tractors and vocational vehicles; trailers used with combination tractors; and HD pickup trucks and vans. For more information on these categories, please refer to the EPA Phase 2 fact sheet.


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