So, random thought while driving into work the other day. Why do we have three lights on traffic signals? Why not just a green countdown until the lights turn red. Yellows aren't always the same length, and we have no clue when the green is going to change... with a timer we could reduce accidents significantly. There's no more ambiguity about "I had a yellow" after the accident that happened because they yellow was one second, and the person who legally entered on a yellow, but had to cross eight lanes, which given the short yellow, is impossible.