He modeled it after the semaphore system used in British railways, with an arm that goes up and down to indicate whether to stop or go. At night, when it was too dark to see the arms, the traffic signal would switch to using red and green gas lamps.
In order to work, the first traffic light had to have a policeman standing by it at all times to switch the stop and go signals. Once, one of the gas lamps exploded, injuring the police officer. The whole project was immediately scrapped, and traffic lights weren't used again for another 40 years.
Categories:
before,
cars,
Shuffle OMG,
Traffic Lights. invented
