How do the unidirectional traffic lights work?
The newest traffic lights use arrays of ultra-bright LEDs instead of bulbs. They are visible from longer distances, they give off a purer colored light, they use much less electricity, and they are far more reliable. Although individual LEDs within the array can burn out, the entire signal will not fail. Most communities are installing these as older signals are phased out. You still see the conventional, incandescent types mainly in older urban areas.
