A real time traffic control system that includes a plurality of roadside sensors and variable message displays arrayed along the highway connected to the Internet, and communicating with a central computer using the Internet. Each roadside device includes a modem and has a unique internet address. The central computer is programmed to create on demand a plurality of individual virtual communication ports, each of the ports corresponding to each of the unique device addresses, whereby said computer communicates in a quasi-simultaneous manner with all of the roadside devices.