Final answer:
The type of insurance that must be had on motor vehicles with four or more wheels is liability insurance. It is a legal requirement in most states to have liability insurance when operating a motor vehicle.
Step-by-step explanation:
The type of insurance that must be had on motor vehicles with four or more wheels is liability insurance. Liability insurance is designed to cover the cost of damages or injuries caused to others in the event of an accident. It is a legal requirement in most states to have liability insurance when operating a motor vehicle.