stop on Red, Go on Green
At the beginning of the twentieth century, traffic in big cities such as New York and London became busy and hectic. Carriages, wagons horses, and bicycles rushed in every direction, and then were joined by the newest toy of the wealthy, the "automobiles."
In those days, crossing a street used to be a real challenge for pedestrians. There were no rules for drivers. The New York Police Department had to create a special squad to handle traffic.Police officers stood at intersections and tried to direct the traffic, but very often they were run over by vehicles. By 1912, New York City had 38000 motor vehicles. Something had to be done about all the traffic on the streets!
In 1916, the first traffic tower was put up in New York, at the intersection of Fifth Avenue and 42nd Street. A traffic officer controlled three 500-watt lamps.They measured 40 centimeters in diameter, and they were red, amber, and green. However, at the time, red meant traffic in all directions had to stop, amber stopped only east-west traffic, and green stopped only north-south traffic. This was very confusing, so in 1924 the city adopted the system used in railroads: red for stop, green for go, and yellow for slow.This system became standard all over the world.
The first automatic traffic lights were installed in Wolverhampton, England, in 1927. Today computers control traffic lights, and road conditions are much better than they used to be. The only problem is when there is a power outage. The result is often confusion on the streets because the traffic lights don't work.