Durable vinyl lettering and decals for private carriers, farm trucks, and non-commercial haulers
The short answer: no federal rule requires a not for hire decal, so for most trucks it is optional. Private carriers that haul only their own goods (farmers, contractors, landscapers, equipment owners) add it so officers and other drivers can see the truck isn't hauling freight for pay. A few states set rules for specific vehicles; Kansas, for example, requires "farm vehicle not for hire" on both sides of farm trucks registered over 54,000 pounds, in letters at least 2 inches tall, so check your state DOT. There's no federal minimum size for the words either. Size them like the truck's other identification marking, which federal rules require to contrast with the truck and be readable from 50 feet in daylight; in practice that means letters at least 2 inches tall, on both doors, next to your company name. The decal doesn't replace a required USDOT number, and it doesn't exempt the truck from safety rules, which depend on weight and how the truck is used (DOT number vs. MC number). Put it on both sides of the truck, order multi-line layouts as transfer decals so the lines go on aligned, and check your state's commercial vehicle lettering rules before you finalize the layout.
If you drive a truck that carries your own goods and never hauls freight for payment, a not for hire decal tells officers and other drivers exactly that at a glance. Decals.com prints custom not for hire lettering and decals in the size, color, and material your truck needs, shipped directly to you and ready to apply. Each one is a permanent or removable decal you own outright.