The person appointed as county engineer, or chief engineer of the division of public roads within the meaning of this article, shall be a registered professional engineer in the State of Alabama in good standing and, in addition, he shall have had not less than three years’ experience in the maintenance and construction of highways and bridges. The county engineer need not be qualified as a land surveyor in order for the State Department of Transportation to participate in the payment of a portion of said county engineer’s salary as provided in Section 11-6-4.