Add Yahoo as a preferred source to see more of our stories on Google. (WHTM/NEXSTAR) – On many traffic signals found throughout the United States, there is a small light that is placed in between or ...

Show almost anyone in the world a red, yellow and green light, and they’ll instantly associate the colorful trio with a traffic signal. But add another color to the mix, and many will be left in the ...

Adding a fourth light to traffic signals -- in addition to red, green and yellow -- would shorten wait times at street corners for pedestrians, as well as improve traffic flow for both autonomous ...