You notice changes to traffic lights can affect everyone on the road — especially when […] ...

Red and green traffic lights have been around since the 1800s, when British traffic officers used to rotate gas lamps that burned red and green to control the movement of mostly horse-drawn vehicles.

If you ride along a bike path in the U.K. city of Leeds and approach a street, the traffic light can automatically turn green for you—or stay green if you’re already midway across. Traditionally, most ...