Section 17C-17-8a - Tandem-axle load limit for the national system of interstate and defense highways(a) The gross weight imposed on the national system of interstate and defense highways by the wheels of a tandem-axle of a vehicle shall not exceed thirty-four thousand pounds.(b) For the purpose of this article a tandem-axle load shall be defined as the total load transmitted to the road by two or more consecutive axles whose centers may be included between parallel transverse vertical planes spaced more than forty inches and not more than ninety-six inches apart, extending the full width of the vehicle.