You are driving a commercial vehicle with air brakes and experience a sudden loss of air pressure in the service line. What should be your immediate action?

Question: You are driving a commercial vehicle with air brakes and experience a sudden loss of air pressure in the service line. What should be your immediate action?

Answer options: ✅ Maintain control of the steering, activate hazard lights, and apply the emergency/parking brake if safe to do so for a controlled stop.

• Press the brake pedal firmly until the vehicle stops completely.
• Shift to neutral and coast to a stop.
• Increase engine RPM to try and rebuild air pressure.

Correct answer: Maintain control of the steering, activate hazard lights, and apply the emergency/parking brake if safe to do so for a controlled stop.

Explanation: A sudden loss of service air pressure will lead to a reduction in braking ability. The driver must take immediate action to control the vehicle, warn others, and bring the vehicle to a safe stop using available braking systems, often the emergency brake.