The phrase "fuel economy ratings" refers to the miles per gallon (MPG) or kilometers per liter (KPL) rating that a vehicle receives from its manufacturer. This rating is an estimate of how much gasoline or diesel fuel a car, truck, van, or SUV will use in terms of fuel consumption over a certain distance traveled. The higher the MPG or KPL rating, the more efficient the vehicle's engine and aerodynamics are at conserving energy, which translates into better gas mileage for the driver and lower emissions from the tailpipe.