== == When its' displaying a S.M.V. placard on the rear - while traveling during daylight hours - under 45MPH - while being used for Agricultural use exclusively. Other than these, ..
That's a state issue. You'll need to contact your state to learn the individual laws. For most states, farm implements, meaning those implements, such as tractors and combines, that are not specifically designed for transportation such as trucks and cars are not necessarily required to get a highway license. Your state may be different so you'll need to ask. Many states will require that an ATC that is used as farm equipment be licensed. You'll need to check. Most states have their laws available on the internet. For links to those, see