Summary: This legislation would reauthorize the DERA program through fiscal year 2029 at its current authorization level of $100 million annually. In 2005, Senators George Voinovich (R-Ohio) and Tom Carper (D-Del.) co authored the first DERA, which became law through the 2005 Energy Policy Act. The U.S. EPA administers the DERA program and uses federal funding—in the form of grants and rebates—to help finance the voluntary replacement or installation of retrofits on existing heavy-duty diesel vehicles and engines. Since its enactment, DERA has enjoyed overwhelming bipartisan support. Congress has reauthorized the program twice, through the Diesel Emissions Reduction Act of 2010 and the Consolidated Appropriations Act of 2021.