what was the first city to have a traffic light

The honour of installing the very first traffic light goes to London, England. In 1868, a gas-lit semaphore-style traffic signal was erected outside the Houses of Parliament. Unfortunately, it exploded within a month, injuring a policeman, so the idea was shelved for decades. The modern electric traffic light, as we know it, was first installed in Cleveland, Ohio, USA, in 1914. So, if you're looking for the birthplace of traffic light chaos, London takes the crown—though it took a bit longer for the concept to catch on worldwide.