All such mileage tax, penalties, fees and amounts collected under this chapter shall be paid into the Treasury within 30 days after their receipt and shall be kept separate and apart from all other funds by the Treasurer in a fund to be known as the Motor Carrier Fund.

The Motor Carrier Fund shall be used as follows:

(1) Such amount of money as shall be appropriated for each fiscal year by the Legislature to the Department of Revenue with which to pay the salaries, the cost of operation and the management of the said department shall be deducted, as a first charge thereon, from the taxes collected under and pursuant to this chapter; provided, that the expenditure of said sum so appropriated shall be budgeted and allotted pursuant to Article 4 of Chapter 4 of Title 41, and limited to the amount appropriated to defray the expenses of operating said department for each fiscal year.

(2) For the payment of all necessary expenses, as approved by the Governor, of the Public Service Commission incurred in the discharge of its duties under Chapter 3 of Title 37; provided, that the amount of expense, including salary, travel, equipment, and all items of cost necessary for the enforcement of the provisions of this chapter shall be limited to the amounts appropriated therefor by the Legislature in the general appropriation bill and shall be budgeted, allotted and expended pursuant to Article 4 of Chapter 4 of Title 41. The remainder of said Motor Carrier Fund shall be paid at the end of each fiscal year, or quarterly as determined by the Governor, into the State Highway Fund, to be used for the maintenance and construction of public highways in the state.