The Washington State Department of Transportation's (WSDOT's) site on the World Wide Web displays current traffic conditions for the highways surrounding Lake Washington. The idea is to let drivers find out where the traffic is so they can try to avoid it. Information that's displayed on the site comes from magnetic wire loops embedded in the highway pavement and from more than 200 separate video cameras installed throughout the highway system. In 1996, the video output from 45 of those cameras was hooked directly to WSDOT's web server, allowing anybody with an Internet connection to look through the cameras' lenses.
WSDOT has actually had video cameras and magnetic loops installed in the highways since Interstate 5 was built in the 1960s, says Mahrokh Arefi, an engineer with the department. But before the World Wide Web, there was no way to easily share the information with the public. Today, that has all changed.
Most of these cameras today are connected to a large video switching system at WSDOT's Northwest Region Traffic Systems Management Center in Northern Seattle. Video monitors blanket the walls of the Center, allowing traffic engineers to quickly spot trouble spots and notify the public via ongoing traffic reports. The Center can also turn on ramp metering lights, which slows the rate of new cars being added to the highway.
Many of the cameras can be individually tilted, panned, and zoomed, allowing a person in the traffic center to conduct detailed ...