Fuel economy-maximizing behaviors describe techniques that drivers can use to optimize their automobile fuel economy. The energy in fuel consumed in driving is lost in many ways, including engine inefficiency, aerodynamic drag, rolling friction, and kinetic energy lost to braking (absent regenerative braking). Driver behavior can influence all of these. The city mileage of conventional cars is lower than highway mileage due to: 1) a high proportion of idling time, 2) operation mostly at very inefficient low-output engine operating points, and 3) more frequent braking.