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]

The ChopBox Smart Cutting Board Has a Food Scale, Timer, and Knife Sharper Built Right Into It

ChopBox
ChopBox

When it comes to furnishing your kitchen with all of the appliances necessary to cook night in and night out, you’ll probably find yourself running out of counter space in a hurry. The ChopBox, which is available on Indiegogo and dubs itself “The World’s First Smart Cutting Board,” looks to fix that by cramming a bunch of kitchen necessities right into one cutting board.

In addition to giving you a knife-resistant bamboo surface to slice and dice on, the ChopBox features a built-in digital scale that weighs up to 6.6 pounds of food, a nine-hour kitchen timer, and two knife sharpeners. It also sports a groove on its surface to catch any liquid runoff that may be produced by the food and has a second pull-out cutting board that doubles as a serving tray.

There’s a 254nm UVC light featured on the board, which the company says “is guaranteed to kill 99.99% of germs and bacteria" after a minute of exposure. If you’re more of a traditionalist when it comes to cleanliness, the ChopBox is completely waterproof (but not dishwasher-safe) so you can wash and scrub to your heart’s content without worry. 

According to the company, a single one-hour charge will give you 30 days of battery life, and can be recharged through a Micro USB port.

The ChopBox reached its $10,000 crowdfunding goal just 10 minutes after launching its campaign, but you can still contribute at different tiers. Once it’s officially released, the ChopBox will retail for $200, but you can get one for $100 if you pledge now. You can purchase the ChopBox on Indiegogo here.

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The Reason Some People Never Return Shopping Carts, According to Science

Abandoned shopping carts could be a sign of social dysfunction.
Abandoned shopping carts could be a sign of social dysfunction.
adisa/iStock via Getty Images

On the spectrum of aberrant behavior, leaving a shopping cart in the middle of a parking space doesn’t quite rise to the level of homicide. But poor cart etiquette is nonetheless a breakdown of the social fabric, one in which some consumers express little regard for others by failing to return a cart to its proper place. Why does this happen?

In a piece for Scientific American, Krystal D’Costa examined some plausible reasons why shoppers avoid the cart receptacle. It might be too far from where they parked, they might have a child that makes returning it difficult, the weather might be bad, or they might have physical limitations that make returning it challenging. Alternately, they may simply believe it’s the job of the supermarket or store employee to fetch their used cart.

According to D’Costa, cart returners might be motivated by social pressure—they fear a disapproving glance from others—or precedent. If no other carts have been tossed aside, they don’t want to be first.

People who are goal-driven aren’t necessarily concerned with such factors. Their desire to get home, remain with their child, or stay dry overrides societal guidelines.

Ignoring those norms if a person feels they’re not alone in doing so was examined in a study [PDF] published in the journal Science in 2008. In the experiment, researchers observed two alleys where bicycles were parked. Both alleys had signs posted prohibiting graffiti. Despite the sign, one of them had markings on the surfaces. Researchers then stuck a flyer to the bicycle handles to see how riders would react. In the alley with graffiti, 69 percent threw it aside or stuck it on another bicycle. In the alley with no graffiti, only 33 percent of the subjects littered. The lesson? People might be more likely to abandon social order if the environment surrounding them is already exhibiting signs of neglect.

In another experiment, researchers performed the flyer trial with a parking lot that had carts organized and carts scattered around at separate times. When carts were everywhere, 58 percent of people left the flyers on the ground compared to 30 percent when the carts were cared for.

Social examples are clearly influential. The more people return carts, the more likely others will do the same. There will, of course, be outliers. Some readers wrote to D’Costa following her first piece to state that they didn’t return carts in order to keep store workers busy and gainfully employed, ignoring the fact that the primary function of those staff members is to get the carts from the receptacle and back to the store. It’s also rarely their primary job.

Until returning carts becomes universally-accepted behavior, random carts will remain a fixture of parking lots. And ALDI will continue charging a quarter deposit to grab one.  

[h/t Scientific American]