Washington USDOT Number Requirements
If you run a commercial vehicle in Washington, your truck has to identify itself. This page explains exactly what has to be on the door, how big the lettering has to be, and where the rule comes from — then lets you design the decals yourself.
Both sides of the vehicle must show your legal company name (or a single trade name) and your USDOT number with the letters USDOT in front of it, in a color that contrasts sharply with the door, readable from 50 feet. Plan on letters at least 2 inches tall.
Does Washington add its own rule?
We have not found a Washington-specific marking rule beyond the federal standard, so the federal requirement is what applies to most carriers here. Intrastate-only rules do change, so confirm with your state agency if you never cross state lines.
Source, checked against the official text: www.utc.wa.gov
The federal rule (49 CFR 390.21)
Both sides of the self-propelled CMV must display: (1) the legal name or a single trade name of the motor carrier, and (2) the USDOT identification number preceded by the letters 'USDOT'. If another party's name also appears, the operating carrier's info must be preceded by 'operated by'. Marking must be in letters that contrast sharply in color with the background, be readily legible during daylight hours from 50 feet while stationary, and be maintained.
What goes on your door
- Legal name — exactly as registered, or one trade name you actually operate under.
- USDOT number — with the letters USDOT in front, like USDOT 1234567.
- Sharp contrast — dark letters on a light door, light letters on a dark door. This is the part inspectors notice first.
- Readable at 50 feet — the legal test, and the reason 2-inch letters are the floor.
Need the decals?
Type your USDOT number, pick your size and color, and see it on a truck door before you buy. Sold single or in pairs for both doors.
Picking a letter height
Most Washington carriers order 2-inch letters. Go bigger — 3 or 4 inch — if the door is tall, if you want the number readable from further away, or if you are stacking the company name and number on separate lines. Our designer shows the finished size in inches as you type, and lets you cap the width so the decal fits between the door seams.
Common questions
How big do USDOT numbers have to be in Washington?
There is no single federal number in inches — the rule is that the marking must be readable from 50 feet away in daylight. In practice 2-inch letters are the accepted standard and what inspectors expect, which is why we start our sizes there.
What has to appear on the door in Washington?
Your legal business name or one registered trade name, plus your USDOT number written as USDOT 1234567. If someone else's name is also on the truck, the operating carrier's information has to be preceded by "operated by".
Do both sides of the truck need lettering?
Yes. The rule says both sides of each self-propelled commercial vehicle, which is why we sell these as a pair by default.
Can I use magnets instead of vinyl?
The marking has to stay legible and be maintained. Magnets are legal in most situations, but they fade, slip at highway speed and get stolen. Cut vinyl lasts years and is what we recommend for a permanent truck.
Ready to order? Logo + USDOT on one decal · Custom logo decals
More USDOT guides: USDOT display requirements — size & location · How to apply USDOT decals & magnetic signs · Care & cleaning of USDOT decals · Requirements in every state
USDOT rules in other states: Washington DC · West Virginia · Vermont · Virginia
← USDOT lettering requirements in every state
Martin Graphics is a sign shop, not a regulatory agency. We publish this as a courtesy and keep it as accurate as we can, but rules change and enforcement varies. You are solely responsible for confirming and meeting the requirements that apply to your vehicle or vessel.
Lettering for the whole fleet
Truck door decals, unit numbers, boat lettering, signs and banners — designed and cut in our Southern Illinois shop since 2009.