The International Fuel Tax Agreement (or IFTA) is an agreement between the lower 48 states of the United States and the Canadian provinces, to simplify the reporting of fuel use by motor carriers that operate in more than one jurisdiction.
This tax is required for motor vehicles used, designed, or maintained for transportation of persons or property and: Exceptions exist for recreational vehicles such as motor homes, pickup trucks with attached campers, and buses when used exclusively for personal pleasure by an individual.
Then the average fuel mileage is applied to the miles traveled to determine the tax liability to each jurisdiction.
Any amount of fuel taxes due (or refund) is then paid to (or received from) the base jurisdiction which issued the license.
Audits are conducted only by the base state and fuel bonds are rarely required.