75 Pa.C.S. § 6123.1: Mandatory traffic-control devices in highway work zones.

Each Interstate highway work zone, including a work zone on the Pennsylvania Turnpike, with a project cost exceeding $300,000 shall be equipped with speed-monitoring devices for purposes of advising the operator of a vehicle of the vehicle's rate of speed. The speed-monitoring device shall be located at least 500 feet prior to entering the work zone. The entity responsible for performing the construction or maintenance work shall erect the speed-monitoring devices in the work zone in accordance with the department's regulations.