miles per gallon MPG stands for miles per gallon and it refers to a common measurement of fuel economy - the average number of miles a vehicle can drive on one gallon of fuel. The higher the MPG, the more economically friendly a car is. MPG, or miles per gallon, is the distance, measured in miles, that a car can travel per gallon of fuel. MPG is also the primary measurement of a car's fuel efficiency: The higher a car's MPG, the more fuel efficient it is. The U.S. Environmental Protection Agency, or the EPA, is the government agency responsible for certifying a vehicle's MPG figures, notes How Stuff Works. A car's MPG can be inconsistent because it is affected by a number of different factors, so it is difficult to get an accurate measurement. For example, factors like traffic and road conditions can affect MPG in any given context. That's why the EPA runs tests over a standard set of courses, then averages the results to calculate a vehicle's official MPG. The EPA gives each vehicle three different MPG ratings, as All Car Leasing notes: Highway MPG: the average a car will get while driving on an open stretch of road without stopping or starting, typically at a higher speed. City MPG: the score a car will get on average in city conditions, with stopping and starting at lower speeds. And, combined MPG, a combined average of highway and city MPG. #carmaintenance #cartips