9.4.3 Traffic Lights

• The world’s first traffic lights were installed near the Houses of Parliament in London in 1868.
  
  
• They consisted of a semaphore arm and were fitted with red and green gas lamps for night use.
  
  
• The first electric traffic lights were installed in Cleveland, Ohio, in August 1914. They were invented by Lester Wire in 1912.
  
  
• The lights were red and green. A warning buzzer sounded when the lights were about to change.
  
  
• The first patent for a traffic signal in the USA was issued to a Mr Morgan in 1923 (patent #. 1,475,024).
  
  
• The patent was for a T-shaped pole with arms that was controlled by an electric clock mechanism.
  
  
• The world’s first 4-way three colour traffic lights were installed in 1920 in Detroit, USA. They were invented by William Potts.
  
  
• In England the first (experimental) automatic traffic lights were set up in Wolverhampton in 1927.