Traffic_light_redTraffic lights are pretty predictable these days. Throughout the country, they’re more or less the same: red, yellow, green. Some might be vertical while others are horizontal, and some places might use arrows more than others, but nothing is too surprising about traffic lights in general.

It wasn’t always like that, though. At one point, traffic was more likely to be directed by police officers than by automated lights. Some places only had two colors, while others had four. Some included “stop” and “go” signs that popped out when the colors changed, and sometimes yellow would appear before red and before green. Crazy, huh?

This 1937 video explores the inner workings of old-timey traffic lights and the cities that used them. Enjoy!