A handbrake is an additional braking mechanism installed on all commercial vehicles that’s completely separate from foot pedal-operated brakes. The role of the handbrake is to both supply an emergency means of stopping if the primary brakes fail – eg if the brake fluid leaks – and also as a parking assist tool. The latter ability is especially useful if a driver needs to park their vehicle on a steep incline.
Critically, handbrakes are purely mechanical braking tools, relying on a series of levers, cables and screws to activate a car’s wheel brakes. In being designed this way, they offer a greater level of safety and reliability than the more complex, if more powerful, hydraulic types. As shown in the diagram below, the handbrake system originates at the front of the vehicle – typically perceived by the user as a lever – and culminates at the rear wheels where the brakes engage to stop a car in its tracks.