There are many vehicles out on the roads with car wraps and magnetic advertisements that are not commercial vehicles, but if it is used or advertising a business it may need a commercial auto insurance policy or at least a business endorsement. Likely you would not need to register your car with the state as a commercial vehicle.
This answer will help you understand if you need a commercial car insurance instead of a personal auto insurance policy with a business endorsement.
State laws do vary you would need to check with your state's Department of Motor Vehicles to be certain about the laws where you live for title and registration information.
Even if your car is not registered as a commercial vehicle your insurance many need to be changed to business use or commercial depending upon the guidelines of your insurance provider. Adding commercial advertising to your vehicle can affect or change your auto insurance requirements. So this could indeed interfere with your auto insurance coverages.
While insurance guideline and policy terms vary we can tell you that in general that many personal auto insurance companies would not cover a car if you place an advertisement, lettering or a magnetic sign for a business on the vehicle. Due to advertising a business on this vehicle, an insurance provider will typically now require you to buy a business auto policy or business use policy instead of a personal auto policy.
In general, vehicles with advertising on them require a commercial auto policy. You will need to check with your specific insurance company to see how they want to cover your vehicle if you place an advertisement for business on it, as a personal auto or business/commercial motor vehicle.
If changes need to be made to your policy, such as changing it over to a commercial / business use policy, then likely you car insurance rates will be affected. So contact your insurance agent to find out what your current insurance provider will require of you, such as changing the policy type, if you place an advertisement on the car. If the rates do rise due to the placement of magnetic advertisements on your vehicle you can shop around for insurance to find lower rates here.
Vehicle advertising can be a gray area with insurers and thus insurance providers vary on what type of insurance you would have to carry on your personal vehicle which you attach magnetic advertisements upon. It is advisable to check with your insurance provider before attaching any advertising to your vehicle to ensure proper auto insurance coverage.
When quoting with CarInsurance.com, either get a Commercial Auto Insurance Quote or when getting a personal insurance quote, select Business, Farm or Delivery as the Primary Use on our Vehicle Quote Screen.