Snapshot: On August 5, 1914 in Cleveland, Ohio, engineers installed a pair of green and red lights facing each side of a four-way intersection — a simple experiment that has since shaped roads around the world, and is honored today in a Google doodle.

The doodle shows the jerky and chaotic traffic flow of a century past. The animation shows cars with the letters spelling “G-O-O-G-L-E” halting at a traffic light and then rushing past it as it turns green.
Gas-lit stoplights appeared in England before the turn of the century, but these had a tendency to explode, and mechanically operated signs that displayed the words “stop” and “move” still relied on traffic attendants.
As automobiles began to appear in US cities in the 1900s, there was no system for dealing with their speed. Sharing the streets with pedestrians and driving unpredictably, they caused alarming numbers of deaths and crashes and prompted police departments to get involved in the business of traffic regulation.
As much as any other invention, the traffic signal gave rise to the carefully controlled, highly automated thoroughfares we think of as roads today.
Google Doodle has been created by Nate Swinehart who hearkens back to an earlier time with shades of black and white, and uses the background colors to make the red and green signals particularly luminous.