We all know what a basic traffic light is supposed to look like. There are three colors — red, yellow, and green — and they’re arranged in that order, either from top to bottom or left to right in a couple of states. Sure, you’ll also see the occasional arrow or blue light on top of a traffic light, but the vast majority follow that basic setup. There’s one traffic light in the United States, however, that completely upends this standard. This light at the intersection of Tompkins St. and Milton Ave. in Syracuse, New York, instead has the green light on top and the red light on bottom.

This light is in the heart of the Tipperary Hill neighborhood. It’s story traces back to the history of Syracuse itself, particularly in the early 20th century. Syracuse can be found along the Erie Canal. During the canal’s construction, a good number of the workers were Irish, and many of them settled on the west side of Syracuse. In fact, the Tippery Hill neighborhood gets its name from County Tipperary in southern Ireland.

If you know anything about Irish history, it involves a tremendous amount of oppression from the British, who ruled the country for hundreds of years. Within this context, this heavily Irish neighborhood wasn’t keen on seeing a beacon in the middle of their neighborhood where green, an Irish color, was placed below red, a British one, when traffic lights began being installed in Syracuse in the 1920s. Some Irish Syracuse youths thought it wise to pelt the traffic light with rocks to break them. This happened numerous times, and the city of Syracuse decided the best course of action was to hang the traffic light upside down in 1928. Since then, the top placement has been Irish green.

While it’s fun that Syracuse gets to have this traffic oddity with the upside down traffic light, there are very good reasons why these specific colors are arranged the same way on every other traffic light. This purely has to do with safety concerns. Out of the three colors used on a traffic light, red is the one with the longest wavelength. This distance gives drivers approaching the light the most amount of time to come to a stop.

The other safety reason you see this configuration on traffic lights is to help drivers who are color blind. Having red, yellow, and green lights is great for most people, but some may struggle to see those distinct colors. For that reason, people know that having the top light illuminated means stop, whereas having the bottom one lit up indicates they can go. There are other ways traffic lights can be color blind hazards, but this standardization helps a great deal for these drivers.

Luckily, it doesn’t seem that this light has made the intersection of Tompkins St. and Milton Ave. a hotbed for car accidents. The Tipperary Hill neighborhood only has a population of a few thousand people — anywhere from 3,300 to 4,349, depending on the source — so it can manage having a standard-breaking traffic light. After all, it’s been a staple of the community for about a century.