- § 393.11
Lamps and reflective devices.
- § 393.17
Lamps and reflectors—combinations in driveaway-towaway operation.
- § 393.24
Requirements for head lamps, auxiliary driving lamps and front fog lamps.
- § 393.25
Requirements for lamps other than head lamps.
- § 393.28
- § 393.40
Required brake systems.
- § 393.41
Parking brake system.
- § 393.42
Brakes required on all wheels.
- § 393.43
Breakaway and emergency braking.
- § 393.44
Front brake lines, protection.
- § 393.48
Brakes to be operative.
- § 393.51
Warning signals, air pressure and vacuum gauges.
- § 393.52
- § 393.60
Glazing in specified openings.
- § 393.61
Truck and truck tractor window construction.
- § 393.62
Emergency exits for buses.
- § 393.65
All fuel systems.
- § 393.67
Liquid fuel tanks.
- § 393.70
Coupling devices and towing methods, except for driveaway-towaway operations.
- § 393.71
Coupling devices and towing methods, driveaway-towaway operations.
- § 393.75
- § 393.76
- § 393.81
- § 393.82
- § 393.83
- § 393.87
Warning flags on projecting loads.
- § 393.88
- § 393.89
Buses, driveshaft protection.
- § 393.92
- § 393.93
Seats, seat belt assemblies, and seat belt assembly anchorages.
- § 393.100
Which types of commercial motor vehicles are subject to the cargo securement standards of this subpart, and what general requirements apply?
- § 393.102
What are the minimum performance criteria for cargo securement devices and systems?
- § 393.106
What are the general requirements for securing articles of cargo?
- § 393.201
Part 393Below are the available interpretations for the given section. To return to the list of parts, use the Parts link above. The menu to the left provides a full list of sections that have interpretations. To view interpretations for a different section, click on the menu item.
The regulations text of the section can be found on the eCFR website. To view the regulations text, use the link below. For assistance, please send an email to FMCSA.Webmaster@dot.gov.
View the regulations for Part 393
Guidance for § 393.75: Tires.
Question 1: If a Commercial Motor Vehicle (CMV) has a defective tire, may the driver remove the defective tire from the axle and drive with three tires on an axle instead of four?
Guidance: Yes, provided the weight on all of the remaining tires does not exceed the maximum allowed under §393.75(f).
Question 2: May a Commercial Motor Vehicle (CMV) be operated with tires that carry a greater weight than the weight marked on the side wall of the tires?
Guidance: Yes, but only if the Commercial Motor Vehicle (CMV) is being operated under the terms of a State-issued special permit, and at a reduced speed that is appropriate to compensate for tire loading in excess of the rated capacity.
Question 3: May a vehicle transport HM when equipped with retreaded tires?
Guidance: Yes. The only Commercial Motor Carrier (CMV) that may not utilize retreaded tires is a bus, and then only on its front wheels.
Question 4: May tires be filled with materials other than air (e.g., silicone, polyurethane)?
Guidance: §393.75 does not prohibit the use of tires filled with material other than air. However, §393.3 may prohibit the use of such tires under certain circumstances. Some substances used in place of air in tires may not maintain a constant physical state at different temperatures. While these substances are solid at lower temperatures, the increase in temperature from highway use may result in the substance changing from a solid to a liquid. The use of a substance which could undergo such a change in its physical characteristics is not safe, and is not in compliance with §393.3.