August 2012, President Obama announced new standards for American-made automobiles of an average of 54.5 miles per gallon by the year 2025. In April 2018, EPA Administrator Scott Pruitt announced that the Trump administration planned to roll back the 2012 federal standards and would also seek to curb California's authority to set its own standards. Although the Trump administration was reportedly considering a compromise to allow state and national standards to stay in place, on 21 February 2019 the White House declared that it had abandoned these negotiations. A government report subsequently found that, in 2019, new light-duty vehicle fuel economy fell 0.2 miles per gallon (to 24.9 miles per gallon) and pollution increased 3 grams per mile traveled (to 356 grams per mile). A decrease in fuel economy and an increase in pollution had not occurred for the previous five years. The Obama-era rule was officially rolled back on 31 March 2020 during the Trump administration, but the rollback was reversed on 20 December 2021 during the Biden administration. Fuel economy of trucks Trucks are usually bought as an investment good. They are meant to earn money. As the Diesel fuel burnt in heavy trucks accounts for around 30% of the total costs for a freight forwarding company there is always a lot of interest in both the haulage industry and the truck builder industry to strive for best fuel economy. For truck buyers the fuel economy measured by standard procedures is only a first guideline. Professional trucking companies measure the fuel economy of their trucks and truck fleets in real usage. Fuel economy of trucks in real usage is determined by four important factors: The truck technology that is constantly improved by the various OEMs. The driver's driving style contributes a lot to the real fuel economy (different from the test cycles where a standard driving style is used). The maintenance condition of the vehicle influences the fuel efficiency – again different from standardized procedures where the trucks are always presented in flawless condition. Last but not least the usage of the vehicle influences the fuel consumption: Hilly roads and heavy loads will increase the fuel consumption of a vehicle. Unit conversions US Gallons 1 mpg ≈ 0.425 km/L 235.2/mpg ≈ L/100 km 1 mpg ≈ 1.201 mpg (imp) Imperial gallons 1 mpg ≈ 0.354 km/L 282/mpg ≈ L/100 km 1 mpg ≈ 0.833 mpg (US) Conversion from