What is a requirement for a commercial vehicle's parking brake?

The requirement for a commercial vehicle's parking brake is that it must hold the vehicle on any grade when loaded. This is crucial for safety, as it ensures that the vehicle remains stationary when parked, even on inclines. The parking brake's ability to maintain the vehicle's position is vital to prevent accidents, especially in situations where the vehicle may roll away due to gravity if not secured properly.

The design and functionality of the parking brake are developed with the understanding that commercial vehicles can be heavy and may be parked on various types of terrain. Therefore, the ability to hold the vehicle in place under load is a fundamental aspect of the safety features of commercial vehicles. By ensuring that the parking brake functions effectively regardless of the incline, it protects both the vehicle and surrounding individuals from potential hazards associated with unintended movement.