How does the Audi A8 achieve its impressive fuel efficiency?

I've heard the Audi A8 is a fuel-efficient luxury car. How does it achieve this and what features contribute to its efficiency?

The Audi A8 utilizes a mild hybrid system, which combines a gasoline engine with a small electric motor to help improve fuel economy. In addition, the car also has a cylinder deactivation feature, which shuts down half of the engine's cylinders when not needed, thus reducing fuel consumption.

The aerodynamic design of the Audi A8 also plays a big role in its fuel efficiency. The car's sleek lines and active grille shutters help reduce wind resistance and improve overall fuel economy.

The A8 also incorporates start-stop technology, which automatically shuts off the engine when the car is at a complete stop, and restarts it when the driver removes their foot from the brake. This helps save fuel by eliminating unnecessary idling.