I've discussed countdown crosswalk signals before (specifically, the lack of them in New York and the absurdly long countdowns in D.C.).
San Francisco's model makes the most sense to me: The timer counts down until the "don't walk" signal appears. (Crazy, I know.) Well, here in Berkeley, they get a little more creative. Along Martin Luther King Way, the signals often count down, only to switch back to "walk." WTF?
Here's a video shot on Martin Luther King.
I guess the idea is to warn pedestrians that the light *could* be about to change. But if there's no cross traffic, it reverts to "walk."
Still, it's a bit disconcerting. And does it teach people to basically ignore them altogether?
Maybe some traffic engineers out there have thoughts on this.