CFR › Title 49 › Part 538 › §538.949 CFR §538.9Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy linkThe application of 49 U.S.C. 32905(b) and (d) to qualifying dual fuel vehicles is extended to the 2005, 2006, 2007, and 2008 model years.