R 408.42229 Signs generally.

Rule 2229. (1) If conditions warrant the use of a sign size that is not specified in Tables 2 to 5, then the ratio of the height of the identifying panel, such as "DANGER" or "CAUTION," to the width of the sign shall be maintained as prescribed in the tables. (2) Signs shall be removed or covered when the hazard addressed by the sign no longer exists.