Controls ahead (advance notice of regulation)
規制予告(きせいよこく)
Meaning
Gives advance notice (規制予告) of traffic regulations in effect ahead, such as road closures or one-way traffic, so that drivers can decide to take a detour beforehand.
Common mistake on the test
Note that it is not a regulation at that spot but advance notice of a regulation ahead. It is a notice, not the regulation itself.