Placement of an Advance Warning Arrow Board in a construction zone directly below an overhead S5-1 school zone signage w/flasher, also channeling traffic away at an angle on a new path. I would think best practice would require a temporary s5-1 sign along new path?
See photos on my google drive.
Link to full size Example Photos
Section 1A.08 Authority for Placement of Traffic Control Devices
07 Signs and other devices that do not have any traffic control purpose that are placed within the highway right-of-way shall not be located where they will interfere with, or detract from, traffic control devices.
08 Any unauthorized traffic control device or other sign or message placed on the highway right-of-way by a private organization or individual constitutes a public nuisance and should be removed. All unofficial or non-essential traffic control devices, signs, or messages should be removed.
Section 2A.20 Orientation
01 Unless otherwise provided in this Manual, signs should be vertically mounted at right angles to the direction of, and facing, the traffic that they are intended to serve.
Section 2A.16 Standardization of Location
10 Because regulatory and warning information is more critical to the road user than guidance information, regulatory and warning signing whose location is critical should be displayed rather than guide signing in cases where conflicts occur.