What role does the parking brake play when starting on a hill?

The parking brake is crucial for preventing a vehicle from rolling back when starting on a hill, particularly when a driver is transitioning between the brake and the accelerator while engaging the clutch in a manual transmission vehicle. When parked on an incline, engaging the parking brake keeps the vehicle stationary and secure, allowing the driver to focus on the delicate balance between the clutch pedal and throttle without the added concern of rolling backward.

When the driver is ready to move, they can release the parking brake at the moment they apply power to the engine, which helps propel the vehicle forward smoothly. This coordination minimizes the risk of stalling or rolling back, which can be particularly challenging for new drivers. Therefore, the primary function of the parking brake in this scenario is to maintain stability and control during a potentially precarious maneuver.