PURPOSE: To change rapidly a sign and prevent accidents in advance, by installing regulation signs of a road construction to be rotatabe around a sign post and make the post extensible and driving it by a remote control.

CONSTITUTION: A road regulation sign 5 or the like is installed so as to be rotatble around the post and the post 4 is made to be freely extensible. And a motor 7 driven by solar cells, sensors 11, are installed. When the construction is temporarily suspended, the sign board 5 is turned to make it invisible. When the height of sign board 5 is changed, the post 4 is extended or contracted by a remote control. In this way, the sign can be rapidly and efficiently changed and accidents can be prevented in advance.