Why would a road keep a copy of cars that traverse it? The 'requests' aren't addressed to Comcast, they are addressed to... well, news.ycombinator.com for example.
"The New Jersey Department of Transportation (NJDOT) maintains traffic cameras on many interstates and other New Jersey State highway systems. The cameras are mounted on poles and record traffic conditions, traffic delays, incidents and weather conditions. They are monitored around the clock at NJDOT's Statewide Traffic Management Center.
In the Department's video camera system, video is recorded and retained at NJDOT for seven (7) days. "
Because its traffic lights use video cameras for input, those developers had to debug the system somehow, management kept the functionality enabled because there might be a business case some day, and storage is always getting cheaper.
