Traffic Signals

November 19, 2009

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Profile America — Thursday, November 19th. It’s hard to imagine busy city streets without automated traffic lights to regulate the flow of cars, trucks, motorcycles, bicycles and pedestrians. One of the first traffic signals was patented this week in 1923. The patent was granted to African-American inventor Garrett Morgan, who decided to do something after witnessing a collision between a car and a horse-drawn wagon on a Cleveland Street. Morgan’s three-position signal was used for some years until the now familiar system of green, yellow, and red lights was adopted. Today’s traffic signals regulate the movements of more than 244 million motor vehicles in the U.S. You can find these and more facts about transportation in America from the U.S. Census Bureau online at <www.census.gov>.

Sources: inventors.about.com
www.fhwa.dot.gov/education/gamorgan.htm
Statistical Abstract of the United States 2009, t. 1056
http://www.census.gov/compendia/statab/2009edition.html