The other day I was driving home. I always seem to miss a left turn light and have to wait for it to turn green again. It seems to take forever. I thought it would be nice to know just how long the light is red before it turns green again. Unfortunately I didn't have a clock with a second hand handy. I was however able to figure out how long the light was red within about a second, but not until I got home. Any ideas as to what I did?