Bought a used truck with someone else's DOT number on it? Do this

Why the old lettering has to go

The marking rule (49 CFR 390.21T, the version in effect) requires the legal name or single trade name of the motor carrier operating the truck, and the USDOT number issued to that carrier. Other identifying information is allowed only if it isn't inconsistent with that (390.21T(b)(4)). Another company's USDOT number on your truck is the textbook inconsistency: it identifies a carrier that isn't responsible for the vehicle.

If some other name stays on the truck (say a dealer or a previous owner's logo you can't remove yet), the rule's fallback is "operated by" followed by your name and USDOT number (390.21T(b)(3)). The cleaner answer is to remove the old marking completely.

Removing old vinyl: heat, low angle, patience

Two film makers' published removal instructions (3M and Arlon) cover the basics:

• Warm it first. Heat softens the adhesive. Arlon's fleet removal tip sheet says to heat the area evenly to about 125 F, and warns that above that the vinyl may delaminate and leave adhesive behind. 3M's bulletin lists industrial heat guns among acceptable heat sources and gives temperature ranges that vary by film type, so if you know the brand, follow that maker's numbers.
• Peel low and slow. Arlon says to pull at about a 15 degree angle and never more than 90 degrees.
• Not when it's cold. 3M notes film turns brittle in cold weather and breaks into small pieces, and recommends removing it above 10 C (50 F).
• Skip scrapers on paint. 3M warns most mechanical removal methods damage the surface. Use a plastic tool to lift a corner.

Getting the glue off

For small traces of adhesive, Arlon suggests isopropyl alcohol. For larger patches, an adhesive remover left on for under a minute, then wiped off, then a soapy water rinse to neutralize it. 3M's bulletin says to test any chemical in a small, hidden spot first because some chemicals can damage the finish. Areas that were repainted or have body filler are the most likely to lift paint, per Arlon.

More detail in how to remove vinyl lettering.

Painted-on lettering

If the old name was painted, there's no peel. Your options are a body shop or covering it. Covering is legal only if what shows afterward is your marking alone and it still contrasts sharply and reads from 50 feet.

Then letter it with yours

Once the doors are clean, put on your legal name (or the single trade name on your MCS-150) and "USDOT" plus your number, both sides. Check what FMCSA has on file first with a DOT number lookup. Our USDOT truck lettering comes as one pre-spaced cut vinyl sheet per door, about 15 minutes a door to apply, both doors from $59 with free shipping. You can preview it on a photo of your truck type before you order.