Geograph - photograph every grid square

The first traffic jam was reported in New York in1913! A year later the police department in Cleveland Ohio installed a red and green traffic control, the first permanent installation in the world.20 In 1917, Detroit police Potts made a major improvement in traffic lights, adding a yellow caution light. The first four-direction light came in 1920. Paris received its first lights in 1922, Berlin in 1924, and London in 1931.The most complicated set of lights is in Chongqing City China and the least needed on Ascension Island.