The Reason Traffic Lights Are Red, Yellow, and Green

Bet_Noire/iStock via Getty Images
Bet_Noire/iStock via Getty Images

All around the country, traffic lights help maintain order on roadways by signaling when it’s time to stop (red), slow down (yellow), or continue (green). While the color scheme appears obvious now, it had to have been created and invented somewhere. Here’s how we arrived at these beacons of the transit system.

According to Today I Found Out, traffic lights have origins in the railroad systems of the 1800s. Train engineers needed a way to know when to stop their locomotives and when to slow down. Red was selected for stop since most people associate it with something potentially perilous or serious. (More importantly, red has the longest wavelength on the color spectrum and can be seen from greater distances, allowing operators to begin slowing down sooner.) They also used a white light to indicate a conductor could go and a green light when they were to use caution.

This worked, until it didn’t. Since two of the lights had a colored filter, confusion resulted if one of the lenses fell off, revealing a white light. If a red filter was damaged, for example, a conductor would see the white light and think it was safe to go when it wasn’t. Legend has it that stars could also be mistaken for the lights, causing accidents. To avoid that problem, white was eliminated, yellow was added to indicate caution, and green was shifted to signal it was time to proceed.

Over in England, the railroad system was being adopted for traffic lights, even though there technically wasn’t any vehicular traffic. Instead, people were concerned about horse-drawn carriages moving through town and posing a danger to pedestrians. Railway manager John Peake Knight noticed the issue and told London’s Metropolitan Police he had a solution: a semaphore system that used signals manually raised or lowered by police officers to signal to carriage drivers to stop or slow down. At night, gas-powered red and green lights were used. Thanks to a gas explosion, however, the system didn’t last long.

By the early 1900s, however, it was clear something effective had to be done. In 1913, the year the Ford Model T was introduced, there were more than 4000 casualties on roads, many as a result of intersection collisions. The United States used law enforcement to enforce traffic, using the semaphore method of arm waving to direct vehicles. It was Cleveland engineer James Hoge who suggested tapping into the trolley system to power red and green lights like the ones used on railways. This system didn’t utilize yellow, with officers preferring to blow a whistle to let drivers know the signal was about to change. It wasn’t until 1920 that a Detroit police officer named William L. Potts devised the three-colored system—red, yellow, and green. A few years later, the lights started changing during timed intervals. If it turned red and no traffic was around, a driver could honk to get it to change.

Not all locations used the same colors, however. To avoid confusion, the Federal Highway Administration mandated the red, yellow, and green color scheme in 1935. It also set guidelines for road signs and pavement markings, standardizing many of the road information we see today.

[h/t Today I Found Out]

Koalas Aren’t Bears, So Why Do People Call Them ‘Koala Bears’?

Arnaud_Martinez/iStock via Getty Images
Arnaud_Martinez/iStock via Getty Images

If you—with no prior knowledge of koalas or pouched animals in general—spotted a tree-climbing, leaf-munching, fur-covered creature in the wild, you might assume it was a small bear. That’s essentially what happened in the 18th century, and it’s the reason we still call koalas “bears” today, even when we know better.

In the late 1700s, English-speaking settlers happened upon a small animal in Australia that looked like a small, gray bear with a pouch. It was soon given the scientific name Phascolarctos cinereus, which is derived from Greek words meaning “ash-gray pouched bear.” Essentially, naturalists had named the unknown animal based on its appearance and behavior, and people didn’t realize until later that the presence of a pouch is a dead giveaway that an animal is definitely not a bear.

According to Live Science, koalas and bears both belong to the same class, Mammalia (i.e. they’re mammals). Then their taxonomic branches diverge: koalas belong to an infraclass called Marsupialia. Marsupials, unlike bears, give birth to their offspring when they’re still underdeveloped, and then carry them around in pouches. Even if koalas look just as cuddly as bear cubs, they’re much more closely related to other marsupials like kangaroos and wombats.

Over time, people adopted a name that the Aboriginal Darug people in Australia used for the animal, koala.

But bear still stuck as a modifier, and scientists never went back and replaced arctos (from arktos, Greek for bear) in its genus Phascolarctos with something more accurate. So, technically speaking, koalas are still called bears, even by scientists.

Wondering how you can help the lovable non-bears survive Australia’s wildfires? Here are 12 ideas.

[h/t Live Science]

The Reason Why Button-Down Shirts Have Loops On the Back

Erin McCarthy
Erin McCarthy

The apparel industry has presented a number of intriguing mysteries over the years. We’ve previously covered why clothes shrink in the wash, deciphered the laundry care tags on clothes, and figured out why shorts cost as much as pants. But one enduring puzzle persists: What’s with that weird loop on the back of button-down shirts?

The loop, which is found on many dress shirts for both men and women, is a small piece of fabric that typically occupies the space between the shoulder blades, where the yoke (upper back) of the shirt meets the pleat. While it can be an excellent way to annoy someone by tugging on it, history tells us it originally had a much more pragmatic function. The loops first became popular among naval sailors, who didn’t typically have much closet or storage space available for their uniforms. To make putting away and drying their shirts easier, the loops were included so they could be hung from a hook.

The loops didn’t remain exclusive to the Navy, however. In the 1960s, clothing manufacturer GANT added what became known as a locker loop to their dress shirts so their customers—frequently Ivy League college students—could hang the shirts in their lockers without them getting wrinkled. (The loop was originally placed on the back of the collar.) Later, students repurposed the loops to communicate their relationship status. If a man’s loop was missing, it meant he was dating someone. Women adopted an apparel-related signal, too: wearing their boyfriend’s scarf to indicate they were taken.

Particularly enthusiastic partners would rip the loop off spontaneously, which became a bit of a trend in the ‘60s. At the time, women who had crushes wearing Moss brand shirts complained that their loops were so strong and secure that they couldn’t be torn off.

For people who wanted to have a loop without ruining a shirt, one mail-order company offered to send just the loops to people in the mail.

You can still find the loops on shirts today, though they don't appear to have any social significance. Should you find one that's torn, it's probably due to wear, not someone's relationship status.