Regulatory Guidance
Welcome to the FMCSA Guidance Portal. This web portal is a searchable, indexed database that contains and links to all guidance documents in effect from the Federal Motor Carrier Safety Administration. The guidance documents lack the force and effect of law, unless expressly authorized by statute or incorporated into a contract.
To comment on any guidance document, or to request issuance, reconsideration, modification, or rescission of any guidance document, please identify the guidance document in your request and send it to: FMCSAguidance@dot.gov. NOTE: The FMCSAguidance mailbox is not intended to serve as a mailbox for general inquiries. For inquiries that go beyond the limited purpose of the FMCSAguidance mailbox, please call FMCSA's Information Line (800-832-5660) or visit FMCSA's "Contact Us" page to send your inquiry to the appropriate mailbox.
| Subject | Agency Identifier | Topic | Issued Date |
|---|---|---|---|
| If a 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? | FMCSA-VEH-393.75-Q01 | Removal of defective tire from set of dual tires | |
| May a vehicle transport HM when equipped with retreaded tires? | FMCSA-VEH-393.75-Q02 | Retreaded tires to transport hazardous material | |
| May tires be filled with materials other than air (e.g., silicone, polyurethane)? | FMCSA-VEH-393.75-Q03 | Filling tires with material other than air | |
| Do tires marked ‘‘NHS’’ (not for highway service) mean that highway use is prohibited by § 393.75? | FMCSA-VEH-393.75-Q04 | Use of tires not for highway service on the highway |