The role of the brakes. The job of the brakes, used in any motor vehicle, is to reduce the driving speed, stopping the vehicle and immobilizing it when stationary. Every motor vehicle should be equipped with at least two braking systems, activated from the driver's seat and operating independently of one another. These are: the main braking system (basically a foot brake) and auxiliary brake system (basically a handbrake). Service brake (pedal) works on all wheels, a auxiliary (manual) on the rear wheels of the car or on the main shaft of the gearbox. Each brake system consists of two units: the brake mechanism and the control system actuating the mechanism. The deceleration in vehicle movement is due to the operation of the brake mechanism, activated by the control system. The most commonly used are friction brake mechanisms. The speed of the vehicle can also be reduced by the so-called. engine braking, by reducing the engine speed and possibly engaging one of the lower gears. The operation of the friction brake mechanism is to convert the kinetic energy of the braking vehicle into heat, resulting from the resistance of mechanical friction between the elements pressed together, one of which rotates, and the other is motionless.