Traffic lights are an integral part of maintaining order among vehicles, cyclists, and pedestrians. And while an agreement has been in place since the late 1960s standardizing intersection lights ...

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.

They might be vertical, they might be horizontal, but otherwise, traffic lights have hardly changed in a hundred years. Red means stop, yellow means slow down, and green means go, a universal code ...