The combination trap
Under the federal definition in 49 CFR 390.5T, a vehicle in interstate commerce is a commercial motor vehicle at 10,001 lbs or more. The test counts the weight rating (GVWR for one vehicle, GCWR for a truck and trailer together) or the actual weight on the scale (GVW or GCW), whichever is greater. For a hotshot, the trailer counts.
Example numbers only: a pickup that weighs 8,000 lbs with fuel and driver, pulling a gooseneck that weighs 7,000 lbs loaded, is a 15,000-lb combination on the scale. It works the other way too. Running empty does not lower a rating, so a rig rated over the line stays over it.
Find your numbers first
- Truck GVWR: the certification label on the driver's door edge or door-jamb pillar.
- GCWR: often not on the door label. Look in the owner's manual or the maker's towing guide for your cab, engine and axle setup.
- Trailer GVWR: the trailer's VIN tag, usually near the front of the frame.
- Actual combined weight: a scale ticket with the rig loaded the way you really run.
Our GVWR explainer sorts out the four terms.
What goes on the truck
If your rig is a CMV in interstate commerce, 49 CFR 390.21T requires two things on both sides of the power unit: your legal name or single trade name exactly as on your MCS-150, and "USDOT" followed by your number, like USDOT 1234567. The marking must contrast sharply with the paint and be legible from 50 feet in daylight.
On a hotshot rig the power unit is the pickup, so the marking goes on both truck doors, not the gooseneck (more in do trailers need USDOT numbers). No inch height is named federally. Our house minimum is 2-inch numbers and 3-inch names, which is shop practice, not a legal number. The hotshot compliance kit is cut to those sizes for pickup doors.
MC numbers, "not for hire" and paperwork
The federal marking rule asks for name and USDOT number only. It does not require an MC number on the truck. Many for-hire carriers show it anyway by custom, and we recommend it if you have one. See USDOT vs MC number.
The weight part of the 390.5T definition does not ask whose freight is on the trailer, so a private rig over the line gets the same marking. A NOT FOR HIRE decal does not replace it.
Operating authority, driver licensing, registration and fuel-tax credentials are separate rules a decal does not cover. Check those with FMCSA and your state agency.
If you stay in one state
Intrastate-only rigs follow state rules, and several count combination weight too:
- Pennsylvania: 17,001 lbs, rating or actual, single or combination, whichever is greater (67 Pa. Code § 231.8(1)). A pickup pulling a heavy trailer can cross it. See Pennsylvania USDOT decals.
- Connecticut: 18,001 lbs on GVWR, GCWR, GVW or GCW (Conn. Gen. Stat. § 14-163c(a)).
- South Carolina: 10,001 lbs, marked USDOT 1234567 SC. The SCDMV intrastate DOT FAQ says a pickup that only goes over 10,001 lbs combined when towing may use removable magnetic signs while towing (not wrecker service vehicles). See South Carolina USDOT decals.
Other states draw the line elsewhere. Start with intrastate USDOT requirements.
Laying out a pickup door
- Measure the flat area below the window and between the body lines. Dually doors and handles take more room than you expect.
- Rule of thumb: about 0.8 inch of width per character for every inch of letter height. USDOT 1234567 at 2 inches runs about 21 inches.
- A long name at 3 inches may need two lines.
- Send a door photo with your order. We lay the stack out on it and email a free proof before anything is cut.
FAQ
My pickup is under 10,001 lbs by itself. Does this apply?
It can. The 390.5T test includes the combination rating and the actual combined weight, whichever is greater. If truck and trailer together reach 10,001 lbs in interstate commerce, the rig is a CMV and the marking goes on the truck.
Does the USDOT number go on the gooseneck too?
The required marking goes on both sides of the power unit, your truck. Lettering the trailer is your call, but it does not take the place of the truck doors.
Can I use magnets on a part-time hotshot truck?
We have not verified a federal answer on magnets either way, so we do not make a federal call. South Carolina allows them in the towing case above. Read magnetic vs vinyl before you choose.
Decals for this
Have your USDOT number, your legal name exactly as on your MCS-150 and the GVWR from the door label ready. Free digital proof, free U.S. shipping, ships 1-2 business days after you approve (3-5 for 30+ sets with multi-color logos).
- Hotshot Trucking Compliance Kit, from $54.95: name, USDOT and GVWR lines for both pickup or dually doors, MC line optional.
- Custom USDOT Number Decals, from $16.00: just the USDOT line if your name is already on the doors.
- USDOT Magnetic Door Signs, from $34.95: for a steel-door truck that only hauls part-time.
Lettering for your trade
Pages written for one trade's vehicle, customers and state rules: carpet cleaning van lettering, electrician van lettering. See every industry.
General information, not legal advice. Rules change — confirm current federal and state requirements with the FMCSA and your state agency before you operate. Our state summaries were verified against primary sources July 2026.
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