EPA & DOT Issue Proposal for Phase 2 of Medium- and Heavy-duty Vehicle Fuel Efficiency & GHG Rules

On June 19, 2015, EPA and DOT jointly published a Notice of Proposed Rulemaking for Phase 2 of their medium- and heavy-duty vehicle fuel efficiency and greenhouse gas rules, applicable to vehicles built starting in model year 2021. Generally, the structure and compliance mechanisms of the proposed Phase 2 rules are the same as the Phase 1 rules, but the proposed Phase 2 fuel use and GHG limits are significantly more stringent: up to 23 percent more efficient compared to model year 2019 vehicles when fully implemented in model year 2027. EPA and DOT are also proposing to regulate commercial trailers for the first time beginning in the 2018 model year, as trailers were not included in the Phase 1 rules. This Issue Brief provides more information on the proposed rulemaking.