Most older vehicles came standard with drum brakes, a brake booster was not really needed. Drum brakes are easier to modulate and the driver could apply enough pressure in an emergency situation to stop in time. With newer disc brakes, however, the effort is much increased when compared to drums. The brake booster was implemented in order to hydraulically assist in applying braking pressure to the calipers. Using a vacuum powered by the vehicle's engine, the brake booster multiplies the force exerted on the master cylinder by your foot when it presses the brake pedal. This results in a much more comfortable driving experience and shorter emergency stops.