Traffic light design

I was checking out the Ask E.T. forum on Edward Tufte's website and stumbled upon this thread about traffic light design. While this sounds like the ultimate exercise in navel pondering by a bunch of designers, it is actually a very interesting topic to consider.

It turns out that many cities around the world have been tinkering with the basic red-yellow-green configuration of traffic lights to include blinking (in order to add more states). The problem is that cities like Boston use blinking differently than they do in Montreal or Taipei (which could lead to disastrous results for travelers).

The coolest idea that I did see was the countdown method being used in cities like Washington D.C. There, the pedestrian crossing signals have a countdown to indicate how much longer you have to cross or how much longer you have to wait until you can cross.