The first traffic signals in Britain (and indeed the world) were installed outside the Houses of Parliament on 10 December 1868. They used contemporary railway signalling technology – semaphore arms for day-time use and green or red gas lamps at night. Unfortunately, they exploded on the night of 2 January 1869 injuring the police constable operating them! The first electric stop-go traffic lights were installed in Cleveland, Ohio in August 1914, with the first three-colour traffic lights in Detroit in 1919. 1922 saw the first electrically synchronised traffic signals installed in Houston, Texas. In Great Britain, manually operated three-colour traffic lights were first used in Piccadilly, London, in 1926, with automatic traffic lights making their first appearance on an experimental basis in Princes Square, Wolverhampton, during November 1927. The experiment was presumably a success and the lights became permanent in 1930. Pedestrian-operated street-crossing lights were first erected on the Brighton Road, Croydon, Surrey in 1932.