[joeyo]

Sounds a little bit like (though more sophisticated than) the timed lights that some cities employ, for example Oak and Fell streets in San Francisco. If you go the speed limit you'll get green all the way though; if you speed you'll just sit at a red light.

[stevep98]

I'm pretty sure there was a light that did this in Virginia. Possibly on Route 7 North of Reston. Long stretch of road with no intersections, and a light seemingly for no purpose.