Engineering, inspection and administration expense in connection with any farm-to-market road project may be paid from said county’s allotment of the farm-to-market road fund. Any such expense incurred by the department may in the first instance be advanced out of the primary road fund, said amounts later being reimbursed to said funds out of the farm-to-market road fund.
Provided, that no part of the salary or expense of the county engineer, any member of the county board of supervisors, any member of the department, the chief engineer, or any department head or district engineer of the department shall be paid out of the farm-to-market road fund.