Location of Detour Markers.
—The location or arrangement of detour markers in reference to the traveled way has received considerable attention. Of course the first signs are the barricade warning and at the barricade. In Illinois the State Department of Highways requires the barricade warning to be placed about 400 feet from the barricade. The map signs of Wisconsin, Minnesota, and North Carolina are used also as barricade signs. Any driver, not authorized, passing a barricade is by the laws of some states subject to arrest and fine. Detour arrows are placed at road intersections in such a manner that traffic going in either direction may follow the arrow. Illinois uses a black arrow on a white background. Iowa has somewhat similar signs except that the color scheme is a white arrow on a black background. The word “detour” is printed above and below the arrow and the one painted out that is not needed after the sign is erected. In Iowa upon primary (State) roads the district engineer, and upon county roads the county engineer, is held responsible for the following:
First.—He shall determine whether or not a detour is needed.
Second.—He shall coöperate with the local officials in choosing a detour.
Third.—He shall provide for the proper marking of the detour.
Fourth.—He shall provide for the maintenance of the detour and report such provision in the central office.