An active construction zone speed limit shall be effective when signs giving notice of that speed limit are prominently displayed in proximity to the active construction zone and construction, repair, maintenance or survey work is performed. Such signs may display either a fixed speed limit or an electronic message that displays adjusted speed limits when work is being performed. The signs shall notify motorists that the fine for a violation of the posted speed limit is doubled in the active construction zone.
Mass. Gen. Laws ch. 90, § 17D