Energy-efficient driving

Energy-efficient driving techniques are used by drivers who wish to reduce their fuel consumption.

Terms for driving techniques to maximize fuel efficiency include hypermiling.

Simple fuel efficiency techniques can result in a reduction in fuel consumption without resorting to radical fuel-saving techniques that can be unlawful and dangerous, such as tailgating larger vehicles.

Underinflated tires wear out faster and lose energy to rolling resistance because of tire deformation. The loss for a car is approximately 1.0% for every 2 psi (0.1 bar; 10 kPa) drop in pressure of all four tires. Wheel alignment, fuel evaporation while parked, and high engine oil kinematic viscosity, all reduce fuel efficiency.

Drivers can also increase fuel efficiency by minimizing transported mass, i.e. the number of people or the amount of cargo, tools, and equipment carried in the vehicle. Removing common unnecessary accessories such as roof racks, brush guards, wind deflectors (or "spoilers", when designed for downforce and not enhanced flow separation), running boards, push bars, and narrow and lower profile tires will improve fuel efficiency by reducing both weight and aerodynamic drag. Some cars also use a half size spare tire, for weight/cost/space saving purposes. On a typical vehicle, every extra 100 pounds increases fuel consumption by 2%. Removing roof racks can decrease fuel consumption by 20%.

Maintaining an efficient speed is an important factor in fuel efficiency. Optimal efficiency can be expected while cruising at a steady speed, at minimal throttle and with the transmission in the highest gear (see Choice of gear, below). The optimum speed varies with the type of vehicle, although it is usually reported to be between 35 mph (56 km/h) to 50 mph (80 km/h). For instance a 2004 Chevrolet Impala had an optimum at 42 mph (70 km/h), and was within 15% of that from 29 to 57 mph (45 to 95 km/h). At higher speeds wind resistance plays an increasing role in reducing energy efficiency.

Hybrids typically get their best fuel efficiency below this model-dependent threshold speed. The car will automatically switch between either battery powered mode or engine power with battery recharge. Electric cars such as the Tesla Model S may go up to 728.7 kilometres (452.8 mi) at 39 km/h (24 mph.)

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Wikipedia