We here at NJ have something called EZPass, all lanes are currently restricted at 15Mph. I've seen those "FAST" toll lanes down in MD, which I think should be the way it works. Having this 15MpH speed limit is such a pain in the nuts.
Oh ... recently they installed speed cameras at each of the EZPass tolls. When you pass it, a digital display tells you how fast you are going. Just for fun ... I always slow down to 15MpH ... then just as my speed shows up on the digital display, I nail the gas as fast as I can. This once I hit 25+MpH at the point of going through the tolls! What a thrill!
Never got a speeding ticket through the polls though.