Why are air brakes considered unsuitable for parking?

Air brakes are considered unsuitable for parking primarily because any leak in the system can lead to a failure in holding the vehicle securely in place. If there is a loss of air pressure due to a leak, the brake system can release and no longer apply the force necessary to keep the brake engaged. This is critical because parked vehicles must remain stationary, and the failure of the air brake system to maintain pressure directly impacts the safety and stability of the vehicle when parked.

While temperature changes, maintenance requirements, and the potential for freezing in cold conditions can affect air brake systems, the most pressing concern for parking safety is the risk associated with leaks that could compromise the braking capability. Therefore, relying on air brakes for parking could present a significant hazard if any air leak occurs, leading to a lack of control over the vehicle.