What happens if the air pressure in the system drops below a certain level?

When the air pressure in the braking system drops below a certain level, it can adversely affect the ability of the brakes to engage correctly. This drop in air pressure compromises the operation of the air brake system, which relies on pressurized air to activate the brake mechanisms. If the pressure is not sufficient, the brakes may not apply fully or may fail to engage entirely, leading to potential safety hazards when operating the vehicle.

Maintaining the proper air pressure is crucial for the effectiveness and reliability of air brakes, enabling drivers to maintain control over their vehicles. In contrast, the other options do not accurately represent the consequences of low air pressure in the braking system. The vehicle cannot operate safely if the brakes do not function properly due to insufficient air pressure.