49 U.S.C. § 32906 — Maximum fuel economy increase for alternative fuel automobiles

(a) In General — For each model year 1993 through 2019, and for every automobile category except electric automobiles (and, from 2016 on, certain alternative-fueled automobiles described in section 32901(a)(1)(E)), the most that dual-fueled automobiles can raise a manufacturer's average fuel economy is capped: (1) 1.2 mpg for model years 1993 through 2014; (2) 1.0 mpg for 2015; (3) 0.8 mpg for 2016; (4) 0.6 mpg for 2017; (5) 0.4 mpg for 2018; (6) 0.2 mpg for 2019; and (7) 0 mpg — no boost at all — for model years after 2019. (b) Calculation — To apply subsection (a), the Administrator figures the boost by starting with the manufacturer's average fuel economy calculated under section 32905(f) (which uses the favorable dual-fuel formula), then subtracting what the average would be if every dual-fuel model were instead scored only on its gasoline-or-diesel performance, using the formula in section 32904(a)(1). The difference is the boost, which subsection (a) caps.