Whenever it may be necessary to protect any highway hereunder, the board of supervisors by an order on its minutes shall so declare and shall certify the same to the governor of the state, who shall thereupon appoint five suitable freeholders of the county to constitute, and be known as, the road protection commission of such county, and who shall decide and recommend the kind and character of protection necessary, to be approved by the board of supervisors. When such commission shall have been appointed and shall have organized, said commission shall select and employ a suitable engineer, to be approved by the board of supervisors, to make a survey, plans, specifications, and estimates of costs of construction under the direction of the said road protection commission, to be approved by the board of supervisors. When so approved, the board of supervisors may proceed to issue bonds of the county therefor, and the road protection commission shall thereupon advertise for bids and let a contract or contracts therefor. Such contracts shall be submitted to and approved by the board of supervisors, all contracts under this section to be executed by the board of supervisors. The road protection commission and the board of supervisors are authorized and empowered to do all things and to make all expenditures necessary to carry out the purposes hereof.