Countdown to Confusion

The law of unintended consequences is the only law the countdown walk/don't walk lights facilitate.  They don't help the laws meant to mediate between the autos and the people as far as I can tell.

The lights have been installed all over San Francisco, and they are widely touted as an improvement in traffic safety.

I wonder. 

There are many intersections where the stream of foot traffic is steady.  With the seconds flashing like they're predicting a space launch, there never seems a time when pedestrians are simply supposed to stop.  Instead the signal tells the walkers if they can stroll or must sprint.

Personally, when I am on foot I rarely decide I must wait.  After all, I can leap across streets in three seconds if I have to! 

Of  course when I am in my car the timer makes me a wreck.  Just when I think I can safely make a left turn on a yellowing light, a guy will leap from the darkened sidewalk and  into the intersection.  He's satisfied with the knowledge that he can jump to the other side in the remaining two seconds on the clock.  If I don't hit him.  The fact that he suddenly appears in front my moving car doesn't disturb his righteous calmness at all.

Were the timer signals really supposed to be permanent "walk" signs?  What are the new rules to our crosswalks and roads?