1868 traffic light

In 1868, London tried the world’s first traffic light outside the Houses of Parliament, a gas-lit rig devised by railway engineer J. P. Knight.

By day it used semaphore arms; by night, red and green lamps—plus a policeman standing beside it like a very brave tea cosy.

After about a month, it exploded and injured the poor officer, which rather dampened enthusiasm for gas-powered road safety.

Electric, automated signals arrived decades later (1910s–1920s) and, blessedly, were much less prone to detonation.

So yes, 1868 lit the way—briefly—and then reminded everyone that prototyping with open flames on busy roads is a spicy idea.