May windshields and side windows be tinted?

Section § 393.60: Glazing in specified openings.

Question 1: May windshields and side windows be tinted?

Guidance: Yes, as long as the light transmission is not restricted to less than 70 percent of normal (refer to the American Standards Association...

May the information in the stopping distance table be used to determine the stopping distances at speeds greater than 20 mph?

Section § 393.52: Brake performance.

Question 1: May the information in the stopping distance table be used to determine the stopping distances at speeds greater than 20 mph?

Guidance: No, the table is not intended to be used to predict or determine...

What difference, if any, is there between a warning device and a warning signal?

Section § 393.51: Warning signals, air pressure and vacuum gauges.

Question 5: What difference, if any, is there between a warning device and a warning signal?

Guidance: For purposes of §393.51, the terms may be used interchangeably.

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.

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?

...

Are vacuum gauges required on the vacuum portion of vacuum-assisted hydraulic brakes?

Section § 393.51: Warning signals, air pressure and vacuum gauges.

Question 3: Are vacuum gauges required on the vacuum portion of vacuum-assisted hydraulic brakes?

Guidance: No. Section 393.51(d)(2) requires only that CMVs with vacuum brakes (not...

Is the vacuum portion of vacuum-assisted hydraulic brake systems required to have a warning device?

393.51: Warning signals, air pressure and vacuum gauges.

Question 2: Is the vacuum portion of vacuum-assisted hydraulic brake systems required to have a warning device?

Guidance: No. Only the hydraulic portion of vacuum-assisted hydraulic brake systems is...

Is the low pressure warning device required to activate before the tractor protection valve?

Section § 393.51: Warning signals, air pressure and vacuum gauges.

Question 1: Is the low pressure warning device required to activate before the tractor protection valve?

Guidance: No. Section 393.51 does not explicitly require the warning device to...

Are the brakes on a vehicle towed in a driveaway-towaway operation or towed disabled vehicle required to be operable at all times?

Section § 393.48: Brakes to be operative.

Question 3: Are the brakes on a vehicle towed in a driveaway-towaway operation or towed disabled vehicle required to be operable at all times?

Guidance: Section 393.48(c) provides an exception to the requirement...

If a truck or truck tractor manufactured prior to July 25, 1980, and having 3 or more axles, has inoperable brakes on the front axle or some of the brake components are missing, would the vehicle be in violation of § 393.48?

Section § 393.48: Brakes to be operative.

Question 2: If a truck or truck tractor manufactured prior to July 25, 1980, and having 3 or more axles, has inoperable brakes on the front axle or some of the brake components are missing, would the vehicle be in violation...

If a CMV manufactured on or after July 25, 1980 (see § 393.42) has brake components on the front axle, and the brakes are not operable, does the vehicle comply with § 393.48?

Section § 393.48: Brakes to be operative.

Question 1: If a CMV manufactured on or after July 25, 1980 (see § 393.42) has brake components on the front axle, and the brakes are not operable, does the vehicle comply with § 393.48?