Partial payments may be made on any contract for highway improvement under the provisions of this act, as the work progresses. Progress estimates shall be based on materials in place and labor expended thereon, but no more than ninety-five percent of the contract price of the work shall be paid in advance of the full completion of such contract and its acceptance by the state highway engineer. The state and county shall each pay its proportionate share of such partial payments on the certification of the amount thereof by the state highway engineer.
NMS § 67-3-48