All vehicles must be fitted with a foot brake and a park brake.
Most light vehicles use a foot brake that operates through a hydraulic system on all wheels, and a hand-operated brake that acts mechanically on the rear wheels only.
The hand brake system holds the vehicle when it is parked. Some vehicles incorporate a drum brake for the hand brake, in the center of the rear disc brake. Others use a mechanical linkage to operate the disc brake from the hand brake system, or separate hand brake calipers with their own pads.
Some vehicles have the hand brake operating on the front wheels. Some vehicles use a single drum brake on the rear of the gearbox as a hand brake. That's sometimes called a transmission brake.
On a duo-servo drum brake, the cable for the hand brake lever pulls on an actuating lever inside the brake drum assembly. The actuating lever is connected to the secondary brake shoe by a pin, and to the primary shoe by a strut. Movement of the lever forces both shoes against the drum.