Engine Braking
Engine braking is the process of reducing speed by lifting your foot from the gas pedal and shifting down through gears. This works without not having to press on the brakes. When you take your foot off the accelerator, the throttle body valve closes, limiting airflow to the engine. When there is little to no air flowing to the cylinders, a vacuum is created, causing the energy to decrease and the wheels to slow. Engine braking is usually in cars with a manual transmission although this can work with automatic cars.