Is a warning device required in a Commercial Motor Vehicle (CMV) with a single hydraulic brake system which uses the driveline parking brake as the emergency brake system?
Section § 393.51: Warning signals, air pressure and vacuum gauges.
Guidance Q&A
Question 4: Is a warning device required in a Commercial Motor Vehicle (CMV) with a single hydraulic brake system which uses the driveline parking brake as the emergency brake system?
Guidance: No. Warning devices are not required on such CMVs because the driver will be given ample warning of system failure by the movement and feel of the brake pedal.