No board of supervisors of any county shall expend from, or contract an obligation against, the budget estimates for road and bridge construction, maintenance and equipment, made and published by it during the last year of the term of office of such board, between the first day of October and the first day of the following January, a sum exceeding one-fourth (1/4) of such item of the budget made and published by it, except in cases of emergency. The clerk of any county is prohibited from issuing any warrant contrary to the provisions of this section. No board of supervisors nor any member thereof shall buy any machinery or equipment in the last six (6) months of their or his term unless or until he has been elected at the general election of that year. The provisions of this section shall not apply to (i) until January 1, 2020, projects of any type that receive monies from the Local System Bridge Replacement and Rehabilitation Program, the Emergency Road and Bridge Repair Fund, the 2018 Transportation and Infrastructure Improvement Fund or the Gulf Coast Restoration Fund and (ii) to expenditures during calendar year 2019 on deficient bridges in the State Aid Road System or the Local System Road Program that have a sufficiency rating of less than fifty (50) or to a contract, lease or lease-purchase contract executed pursuant to the bidding requirements in Section 31-7-13 and approved by a unanimous vote of the board. Such unanimous vote shall include a statement indicating the board's proclamation that the award of the contract is essential to the efficiency and economy of the operation of the county government.