Commercial Driver’s License (CDL) Practice Exam

During a long descent, a driver should ideally monitor air pressure levels, specifically the air brake system pressure. This is crucial because descending steep grades can generate significant heat, which may lead to brake fade if the traditional braking system is overly relied upon. Air pressure levels indicate whether the brakes are functioning properly and whether there is enough pressure to maintain brake efficiency.

Monitoring air pressure ensures that the air brake system remains operational, providing an essential safety measure when navigating downhill. This also allows the driver to react and take necessary actions, such as using engine braking or downshifting, to prevent excessive reliance on the brakes, which can lead to brake failure.

Other areas such as engine temperature and fuel consumption are important in different contexts, but during a descent, maintaining brake system integrity through air pressure monitoring is critical for safety. Radio interference does not directly impact the vehicle’s operation during a descent, making it less relevant in this scenario.