what is fuel efficiency

Fuel efficiency is a measure of how efficiently a vehicle uses fuel to travel a certain distance. It is a form of thermal efficiency, which is the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. In the context of transportation, fuel efficiency is often expressed as "miles per gallon" (mpg) or "liters per 100 kilometers" (L/100 km) . Fuel efficiency is dependent on many factors, including engine efficiency, transmission design, tire design, weight, aerodynamic drag, AC usage, fuel, and rolling resistance. Improving fuel efficiency can bring a wide range of benefits, such as saving fuel costs, reducing carbon footprint, and cutting dependence on oil. There have been advances in all areas of vehicle design in recent decades, and fuel efficiency of vehicles can also be improved by careful maintenance and driving habits.