The engineer shall, as soon as practicable, submit to the commission in writing his recommendations as to detail plans, width of right-of-way and surfaced roadway and type and character of construction for each county, and at the same time furnish a copy thereof to the county clerk for public information. The commission may approve, disapprove, modify or amend the proposals so recommended, and the action of the commission thereon shall be the action of the department on such subject, and shall not be modified or disturbed except by subsequent action of the commission.