A method, medium and implementing processing system are provided in which the presence of workers in a long highway construction zone is monitored and the electronically-controlled posted speed limit is adjusted in accordance with the detected presence of workers in the immediate area. In an example, Radio Frequency Identification (RFID) scanners or readers are strategically placed in a construction or working area. Such RFID reading devices may be embedded, for example, in construction speed limit signs. The displayed speed limit is controlled by the detected proximity of construction workers wearing RFID-embedded clothing, for example, such as safety vests or helmets. The speed limit sign includes logic to display one of many possible speed limit displays based on the nearest, and/or the number of RFID signals detected in a given area. Vehicular traffic is thereby enabled to travel faster through construction zones where no workers are present and, when appropriate, traffic is slowed when workers are present within a given proximity of the RFID reading devices.