Guides

The rules, in plain English.

One question per page. Checked against the regulations September 2026.

Not sure what your truck needs?

Answer five questions and get the list: USDOT, MC, CA number, CSLB.

Look up a USDOT number

See who a DOT number is registered to, and their lettering on a door.

Rules by stateWhat each state adds to the federal rule: state numbers, formats, sizes. Starting a businessTowing, trucking, hotshot, landscaping, contracting, moving, delivery, dump trucks. Boat numbers by statePrefixes, the 3 inch rule, sticker placement. By vehiclePickups, hotshots, dump trucks, vans, landscaping, plumbing, moving, flatbeds.

Getting your numbers

How do I get a USDOT number?You apply directly with FMCSA online. Since May 2026 that happens in Motus, FMCSA's new USDOT Registration System at motus.dot.gov, which replaced the... Do I need a USDOT number?Under FMCSA rules you need a USDOT number if you operate in interstate commerce with a vehicle or combination rated or weighing 10,001 lbs or more, ca... How do I get an MC number?You apply for operating authority (the MC number) with FMCSA, now in its Motus registration system, and pay a one-time, non-refundable $300 fee per au... What is the difference between a USDOT number and an MC number?A USDOT number is FMCSA's safety ID for your company. It tracks your inspections, crashes and audits, and it's free. An MC number is operating authori... What is the difference between interstate and intrastate for a USDOT number?Interstate commerce, under 49 CFR 390.5, is hauling between states, through another state, or within one state as part of a trip or shipment that star... Do I need an LLC to get a USDOT number?No. FMCSA registers sole proprietors, partnerships and corporations, and its MCS-150 instructions tell a sole proprietor to enter their own legal name... How do I look up a USDOT number?Go to FMCSA's SAFER Company Snapshot at safer.fmcsa.dot.gov, choose USDOT number, MC/MX number or company name, and search. It's free and shows the ca...

Filings and renewals

What is UCR registration and do I need it?Unified Carrier Registration (UCR) is a yearly federal-state registration and fee for companies operating in interstate commerce, including for-hire a... When is my MCS-150 biennial update due?Every company with a USDOT number must update its MCS-150 every 24 months, even if nothing changed. The month is set by the last digit of your USDOT n... What is a BOC-3 filing?The BOC-3 is FMCSA's Designation of Agents for Service of Process. It names a process agent in every state you operate in or through, so legal papers ... What insurance do I need for an MC number?FMCSA requires for-hire property carriers to have bodily injury and property damage (BIPD) liability of at least $750,000 for vehicles 10,001 lbs GVWR... What is IRP registration and do I need apportioned plates?IRP, the International Registration Plan, lets you register a truck once in your home (base) jurisdiction and run it in the other member states and pr... Where do IFTA stickers go and who needs them?You need an IFTA license and decals if you run a qualified motor vehicle in more than one IFTA jurisdiction: two axles and over 26,000 pounds gross or...

Inspections and audits

What is the FMCSA new entrant safety audit?Every new motor carrier is monitored by FMCSA for its first 18 months, and FMCSA conducts a safety audit within 12 months after you start operating. T... What are the DOT inspection levels?Roadside DOT inspections follow the CVSA North American Standard, which has eight levels. Level I is the full inspection of driver and vehicle, Level ... What's the fine for not having a DOT number on my truck?Missing or wrong door markings are a violation of 49 CFR 390.21T (cited as 390.21). As of October 2026, 49 CFR part 386 Appendix B sets the maximum fe...

What goes on the door

Do I need a DOT number on my truck?You need a USDOT number if your truck is used in interstate commerce and it has a gross vehicle or combination weight rating of 10,001 lb or more, hau... How big does my USDOT number have to be?Federal rule 49 CFR 390.21 doesn't give a height in inches. It says the legal name and USDOT number must be in letters that contrast sharply with the ... What color does my DOT lettering have to be?Any color, as long as it contrasts sharply with the paint behind it and can be read from 50 feet away in daylight while the truck is parked. That is t... Do I need my MC number on my truck?No. The federal marking rule, 49 CFR 390.21, only requires your legal or trade name and your USDOT number on both sides of the truck. The MC number do... Do I need a CA number on my truck?If you operate a commercial vehicle for business in California and it weighs over 10,001 lbs GVWR (or hauls for hire), you need a Motor Carrier Permit... Do I need the GVW on my truck door?Federal rules do not require the gross vehicle weight on the door. Only your name and USDOT number are required by 49 CFR 390.21. Some states require ... Can I put my DBA on my truck instead of my legal name?Yes, if it's on file. 49 CFR 390.21T requires the legal name or a single trade name of the motor carrier as listed on its MCS-150. So you can letter t... Are unit numbers on trucks required by DOT?No. The federal marking rule, 49 CFR 390.21T, requires only the carrier's legal or single trade name and USDOT number on both sides; it says nothing a... Do I have to put my CSLB license number on my truck?Yes. California Business and Professions Code 7029.6 requires licensed contractors to display their business name and license number on every commerci... How do How's My Driving decals work?The decal gives the public a way to report a driver: a phone line, a web link, or a QR code, each tied to a code for that vehicle. Reports go to the f...

Which vehicles need it

Does my box truck need a DOT number?Yes if it's used in commerce and rated over 10,001 lbs GVWR, which covers essentially every box truck. In California you also need a CA number. The na... Does a pickup truck need a DOT number?A pickup needs a USDOT number when it is used for business in interstate commerce and its weight rating crosses 10,001 lb. For a pickup alone that is ... Do you need a DOT number for a cargo van?Usually not for a van alone, but it depends on the weight rating. A vehicle used in interstate commerce becomes a federal commercial motor vehicle at ... Do tow trucks need a USDOT number?A tow truck used in interstate commerce needs one when it meets the federal commercial motor vehicle definition: a GVWR or GCWR (or actual weight) of ... Do I need my USDOT number on my trailer?No. The federal marking rule, 49 CFR 390.21, applies to self-propelled commercial vehicles, so your name and USDOT number go on the truck or tractor, ... Does a covered farm vehicle need DOT markings?A covered farm vehicle is a farm-plated truck run by a farmer, family member or employee, hauling farm goods to or from the farm, not for hire and not... If I'm an owner-operator leased to a carrier, whose USDOT number goes on my truck?The carrier's. Under 49 CFR 376.11(c), the carrier you're leased to must identify your truck as being in its service using the marking rules in 49 CFR... Do I need my USDOT number on a rental truck?For a rental of 30 days or less, no, as long as the paperwork is right. 49 CFR 390.21T(e) lets a carrier run a rented CMV marked with the rental compa... Do I have to remove the previous owner's DOT number from a used truck?Yes, before you run it under your company. 49 CFR 390.21T says the marking must show the name and USDOT number of the carrier operating the truck, and... Are magnetic DOT signs legal?Yes. 49 CFR 390.21 lets the marking be painted on or be a removable device, as long as it meets the same requirements: legal name and USDOT number, on...

Lettering how-tos

What is the best kind of lettering for a truck door?For USDOT and company-name lettering, cut vinyl is the usual choice: solid-color letters with no background, applied straight to the paint. Printed de... How much does truck lettering cost?Price comes down to size, how many lines you need, special materials like reflective vinyl, any logo work, and whether someone installs it for you. As... What goes on truck door decals?For a USDOT carrier the decals need two things on both doors: your legal or trade name, and USDOT followed by your number, in a color that contrasts w... How do I measure my truck door for lettering?Measure the flat area of the door you can actually stick vinyl to: the widest stretch without handles, body lines, rivets, seams or trim, and the heig... How do I apply vinyl lettering?Clean the door with alcohol, tape the top edge of the sheet in position, peel the backing from the top, squeegee down from the center outward, then pe... How do I remove vinyl lettering from my truck?Warm the vinyl so the adhesive softens, peel it back slowly at a low angle, then lift any leftover glue with a plastic scraper and an adhesive remover... Is reflective lettering required on trucks?No. The federal marking rule, 49 CFR 390.21, requires your name and USDOT number in sharply contrasting letters readable from 50 feet in daylight, and... What font should I use for truck lettering?Use a bold block or sans-serif font with thick, even strokes and normal letter spacing, in a color that contrasts sharply with the paint. 49 CFR 390.2... How big do CF numbers have to be on my boat?At least 3 inches tall, plain block letters, in a color that contrasts with the hull, on both sides of the forward half of the boat, reading left to r...