My father is a truck driver. He once got ticketed for running a red. He was certain the yellow was too short. He began timing the yellows at that intersection. Doing some math with the stopping distance of a loaded 18 wheeler we determined that there was a point where you couldn't make it thru at the speed limit but you couldn't stop in time either. If you happened to be driving a truck and the light changed when you were at that spot you had too run the red because there just wasn't enough distance to stop.
This was years ago but if I remember right it was a 2 second yellow in a 55 mph zone. I don't know if they ever changed it or not.
