These are the brakes wherein the, power of the engine and / or the battery power is used to enhance the braking effort. These are basically of the four types, the vacuum brakes, the air brakes, the brakes with hydraulic booster and the ones with the electro hydraulic booster. The first three types out of this will be discussed in detail in later sections.

The hydraulic booster systems usually employ pressure from the power steering system to increase pressure on the master cylinder, whereas electro-hydraulic booster systems uses an electric motor to pressure the hydraulic system beyond the brake pedal that is in the entire brake system. The advantage of this system is that even if the engine fails, the power brakes would function so long there is battery power available. In case of vacuum brakes, the vacuum from the inlet manifold is utilized, due to which the vacuum power brakes would not function if the engine is not working.