A person may not operate on a highway which is part of the interstate system any vehicle:
W = 500 (LN/N-1 + 12N + 36)
where W equals maximum weight in pounds carried on any group of more than one axle; L equals distance in feet between the extremes of any group of consecutive axles; and N equals number of axles in the group under consideration, except that two consecutive sets of tandem axles may carry a gross load of thirty-four thousand pounds [15422.14 kilograms] each, providing the overall distance between the first and last axles of the consecutive sets of tandem axles is at least thirty-six feet [10.97 meters]. The gross weight may not exceed eighty thousand pounds [36287.39 kilograms].
N.D.C.C. § 39-12-05