Whenever the board of county road commissioners of any county shall have funds available, the board may enter into a contract or agreement, with any incorporated city or village within the county, assuming the obligations in whole or in part of the city or village undertaken by contract or agreement with the state highway commissioner under the provisions hereof or approved hereby. The board may contract or agree to carry on, in whole or in part, the improvement or construction required thereby, and may institute and conduct condemnation proceedings necessary therefor. No contract or agreement by any board of county road commissioners shall be effective until approved by resolution of the board of supervisors of the county and of the legislative body of the incorporated city or village concerned. The provisions of this section shall not be deemed to abolish, limit or restrict the powers and duties of the state highway commissioner or of incorporated cities or villages as prescribed by this act.