Part of the U.S. CAFE standards, enforced by the NHTSA includes a provision for fines when the requisite levels of efficiency aren't met. That power of enforcement also saw Porsche Cars North America, Maserati Automobiles and Ferrari North America pay fines of $1.1-1.2 million apiece, reports the Detroit Free Press.
In 2008, over $37 million in total fines were assessed on six different carmakers. Mercedes' $28.9 million share accounts for over 78% of that total amount. The now-split DaimlerChrysler's record $30.3 million fine was assessed for vehicles built during the 2006 model year, and was itself due primarily to Mercedes-Benz's vehicles.