The director is hereby authorized to close highways for construction purposes and in emergencies, and shall select, lay out, maintain, and keep in as good repair as possible suitable detours by the most practicable route, where same are necessary for the public convenience while any sections of said highways or roads are being improved or constructed or closed. The director shall place or cause to be placed explicit directions to the traveling public during repair of said highway or road under process of construction. As far as practical roads already laid out shall be connected with and used for such detours.

The director is hereby authorized, subject to the approval of the commission, to enter into agreements, spread on the minutes of both boards, with the local road authorities of the county or counties in which construction or maintenance work is to be done, to pay all or any part of the cost of laying out or maintaining said detours. All expenses to the state of laying out and maintaining said detours shall be paid out of the state highway funds. The director is also authorized, subject to the approval of the commission, to make reasonable rules and regulations to keep highways under construction open to traffic where such action is deemed to be practical and desirable.

If any county-maintained road or municipally-maintained street is used temporarily as a part of a state highway detour, it shall be the duty of the highway department, when said detour is abandoned as such, to place the same in as good condition as said road or street was when its use as a detour began.