http://webapps.cityofchicago.org/traffic/
Check the Camera box and the intersections with cameras appear. Click on any camera to see which directions of travel are being monitored.
I found that one too, I used it to clear alot of mislabeled lights. I found another site too for other cities, but I found several listed that I know aren’t there. Seems like the Chicago one has been kept up to date.