(c) As used in this Section, a "construction or maintenance speed zone" is an area in which the Department, Toll Highway Authority, or local agency has posted signage advising drivers that a construction or maintenance speed zone is being approached, or in which the Department, Authority, or local agency has posted a lower speed limit with a highway construction or maintenance speed zone special speed limit sign after determining that the preexisting established speed limit through a highway construction or maintenance project is greater than is reasonable or safe with respect to the conditions expected to exist in the construction or maintenance speed zone. If it is determined that the preexisting established speed limit is safe with respect to the conditions expected to exist in the construction or maintenance speed zone, additional speed limit signs which conform to the requirements of this subsection (c) shall be posted.
Highway construction or maintenance speed zone special speed limit signs shall be of a design approved by the Department. The signs must give proper due warning that a construction or maintenance speed zone is being approached and must indicate the maximum speed limit in effect. The signs also must state the amount of the minimum fine for a violation.