They have, Around arlington or alexandria va, the local govt said it is for public safety ( yea right >_>) while an independent study suggest it's caused more accidents, people now slam on the breaks not to get it, some lights have short yellows and can still get it if they don't make it, and the amount of money it will make in a few years is about a billion. People has also gotten tickets from blocking this cameras, and other thing I hate about them is you cannot fight it in court then, and no one is really honest to say, yea it's about revenue. Or if a relative/friend is in the hospital (emergency) and sometimes you gotta speed there and a cop pulls you over they might let you go or tell you to slow down with these, won't happen now..
And area's with speed cameras, guys I used to listen on the radio (used to live in) Arizona and places that they get calls from says when people know they are near one everyone slows down.