Many cities are replacing their incandescent traffic lights with LEDs, despite the higher initial cost. Here's why that's ...

Before we’re old enough to even see over the dashboard, we learn that green means go and red means stop. This internationally recognized traffic light color system is standard in most of the world.

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.