The Reason Why Stop Signs Are Red

Roman_Gorielov, iStock/Getty Images Plus
Roman_Gorielov, iStock/Getty Images Plus

Why is red the standard color for stop signs? The short answer is this: because the representatives of the First National Conference on Street and Highway Safety in 1924 decided so.

Though stop signs were still a relatively new idea in the United States back in the 1920s—Detroit erected the first one around 1915, Jalopnik reports—the “red means ‘stop’” custom dates back to 1841, when Henry Booth of the Liverpool and Manchester Railway suggested using red to indicate danger on railroads. London then adopted the color for its regular traffic lights in 1868, and the United States eventually followed suit.

The First National Conference on Street and Highway Safety, called by then-Secretary of Commerce Herbert Hoover in 1924, aimed to standardize the color coding of road signage. It established that for all “signs and signals, both luminous and nonluminous,” red should indicate “stop,” green should indicate “proceed,” and yellow should indicate “caution,” according to the report released after the conference [PDF]. It was also decided that distance and direction signs should be black and white.

That all probably sounds familiar if you’ve ever seen a street before, but implementing the mandate for red stop signs posed immediate issues. A red material that wouldn’t fade over time just didn’t exist in 1924, Gene Hawkins, a professor of civil engineering at Texas A&M University, told The New York Times in 2011. So the writers of the 1935 Manual on Uniform Traffic Control Devices chose the next best thing: yellow. The manual also specified that every sign should be octagonal, another idea from the 1920s.

California was first to figure out that porcelain enamel would resist fading and erect red stop signs across the state, a practice noticed and addressed in the 1954 revision [PDF] to the Manual on Uniform Traffic Control Devices. Now that red was more logistically feasible, the committee in charge of updating the manual decided there should be no more yellow stop signs.

We don’t know exactly why Henry Booth and other early industrialists felt that red aptly signaled “stop.” Maybe they thought it was harder to overlook than blue or green, which natural surroundings like water and foliage might easily camouflage. Maybe they felt red, like fire or blood, just went along well with danger.

There may also be a deeper reason. When, as part of a 2011 study, red-, blue-, and green-clad human experimenters offered apple slices to individual monkeys in a free-range facility, the monkeys seemed to have an aversion to taking slices left by the experimenter wearing red. Perhaps our association of danger with the color red has a psychological basis we don’t fully understand yet.

[h/t Jalopnik]

The Reason Why Baking Makes You Feel Good, According to Psychologists

Liderina/iStock via Getty Images
Liderina/iStock via Getty Images

Whether you're nibbling a slice of zucchini bread or an extra-chewy chocolate chip cookie, it’s always fun to be the taste tester for a friend or relative who loves to bake. And, while eating products created with love (and sugar) probably makes you feel good, the baker is reaping some psychological benefits, too.

Studies have shown that creative activities like baking and knitting contribute to an overall sense of well-being. Boston University associate professor of psychological and brain sciences Donna Pincus told HuffPost that there’s “a stress relief that people get from having some kind of an outlet and a way to express themselves.”

Baking is also a great way to practice mindfulness, because it requires you to focus on following very straightforward directions in a specific order. In other words, most of the decisions have already been made for you, allowing you to concentrate on the details while nudging your mind away from the stressors and anxieties of your life outside the kitchen. Julie Ohana, a licensed clinical social worker and culinary art therapist, explained to HuffPost that baking is therapeutic because it helps you practice the “balance of the moment and the bigger picture.” While you’re measuring and mixing ingredients, you’re probably visualizing how they’ll all come together to create a fulfilling final product, and deciding how and when you’ll share it with others.

Sharing your desserts—altruistically rather than for attention or competition—is another mood-booster, making you “feel like you’ve done something good for the world, which perhaps increases your meaning in life and connection with other people,” Pincus said. It can also function as a mode of communication. Susan Whitbourne, professor of psychological and brain sciences at the University of Massachusetts, told HuffPost that “it can be helpful for people who have difficulty expressing their feelings in words to show thanks, appreciation, or sympathy with baked goods.”

If baking just isn’t for you, that’s OK, too—try one of these other stress-reducing tactics instead.

[h/t HuffPost]

The Reason Why Objects in a Car’s Side-View Mirror Are Closer Than They Appear

aydinozcanbaz/iStock via Getty Images
aydinozcanbaz/iStock via Getty Images

“Objects in mirror are closer than they appear.” It's a warning you see in basically every car, but why can't passenger-side mirrors display objects accurately? Well, it's actually a careful design choice made with safety in mind.

The way we see things is dependent on how light reflects off objects around us. An object's color, texture, shape, and other characteristics influence the direction and intensity of light that bounces off them. If the objects are reflected off an intermediate object, like a mirror, our perception of the original object may be distorted.

The shape of the mirror also makes a difference in our perception. In the U.S., passenger-side mirrors are convex (curved slightly outward), whereas driver-side mirrors are flat. A convex mirror placed on the passenger side reduces the driver's blind spots on that side of the vehicle by presenting a wider field of view, but it also makes other cars appear farther away due to a slight distortion caused by the shape. The flatter mirror on the driver’s side produces a more accurate depiction of what’s behind the car with a more narrow field of view, since light bounces off in the same direction that it hits the mirror and doesn't distort the reflection of the object.

When the two mirrors' reflections are combined in the driver's point of view, drivers have the ability to both see wider areas on the passenger side while keeping their eyes (mainly) on the road. The flat-convex combo has been the U.S. standard for years, though the U.S. Department of Transportation is looking into the safety benefits of two convex mirrors, which European cars usually sport.

For now, always remember to check your mirrors frequently, and look over your shoulder before you change lanes. (Don't forget your turn signal!)

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