On or before the time fixed by law for the closing and final adoption of the annual tax budget of the county, the board of chosen freeholders shall appropriate either in the annual tax budget or separately the county’s share of the estimated cost and expense of all work contracted for under the provisions of this article since the day fixed by law for the closing and final adoption of the annual tax budget of the county in the year next preceding, which shall be the total cost of such work less the amount certified to be paid by the state.

The sum or sums so fixed and appropriated shall be certified to the county board of taxation and shall be included in the assessment of county taxes and shall be assessed, collected and paid over to the county in the same manner and at the same time as other county taxes. If a deficiency shall exist in consequence of the cost and expense exceeding the estimate, or in consequence of the receipt of a lesser sum from the state as its share of the total cost and expense than shall have been estimated or fixed, the board of chosen freeholders may borrow, on temporary loans, such deficiency, and shall include the amount thereof with accrued interest in its next annual budget and tax resolution, and it shall be assessed, collected and paid over in the same manner as other taxes, or the deficiency may be raised by an issue of bonds either separately or in conjunction with an issue to pay the cost and expense of improving any other road under this article.

If, for any reason, there be a surplus, it shall be retained and used in the improvement of other roads under this article or in repairs to roads improved under this article.