36. Where a road vehicle is equipped with hydraulic, pneumatic or vacuum-boosted hydraulic service brakes, or with a hydraulic boost system aided by an electrically driven hydraulic pump, is must be possible to evacuate the power reserve by depressing the pedal several times with the engine off. After that, the pedal shall drop slightly under the foot with a moderate pressure (about 90 newtons) while starting the engine and, in the case of a hydraulic boost system, the electric motor shall start when the ignition key is in the “on” position while the engine off.