(1) The tax on the use of special fuel by any special fuel user does not apply to the use of fuel in a motor vehicle operated exclusively off the public road. If a motor vehicle is used both on and off the public road, the special fuel tax liability does not apply to the special fuel used to operate the motor vehicle on that portion of travel off the public roads.

(2) Each special fuel user, except those covered under 15-70-362 , MCA, must maintain adequate records of the operations off the public roads, the miles traveled, and the special fuel used to establish that the special fuel user is entitled to the credit for off public road use of such fuel.