What's really nice are the crosswalk signals with a countdown. They let you know how much time before the light changes.
Some of the more busy intersections also have lights that will show red in all four directions for a couple seconds before the light changes.
I don't know when yellow became mandatory. I do know, however, that the first 3 color signal was invented in 1920 by William Potts of the Detroit Police Department. It used four-inch railroad lenses. (Bonus if you can name the type of lens that would have been) The original signal is actually still in existance and hangs at the Henry Ford Museum in Dearborn, MI.
Some of the more busy intersections also have lights that will show red in all four directions for a couple seconds before the light changes.
I don't know when yellow became mandatory. I do know, however, that the first 3 color signal was invented in 1920 by William Potts of the Detroit Police Department. It used four-inch railroad lenses. (Bonus if you can name the type of lens that would have been) The original signal is actually still in existance and hangs at the Henry Ford Museum in Dearborn, MI.