Why America's traffic signs look so much different from the rest of the world
American exceptionalism had a lot to do with it.

Why are traffic signs so differnt in the U.S.?
Have you ever watched a James Bond movie and noticed that as he races his Astin Martin through the hills of an exotic European locale, the street signs look a lot different than those in America? Did you also notice that they don’t have many words, mostly shapes and pictures?
It isn’t by accident. Many years ago, there was a movement to get America on board with the rest of the world so all of our street signs would be the same, but it never happened. For better or worse, America, once again, exercised its independent spirit and stuck with its signs.
The whole story was recently told on YouTube by Half as Interesting. This channel prides itself on being an “Education-y explainer videos that are almost good enough to watch.”
The chasm between the U.S. and the rest of the world regarding traffic signs started in the early 1900s when Henry Ford began mass-producing automobiles and America quickly became the car capital of the world.
This also made the U.S. the road capital of the world.
Why US Signs Look Different Than The Rest Of The World’s
The signage across the U.S. in the early days of the automobile was inconsistent, which would cause problems as people drove from region to region and couldn’t make sense of the signage. So, in 1931, a committee of traffic sign organizations created a joint committee that ultimately came up with the 1931 Manual on Uniform Traffic Control Devices.
This Bible of signage gave us the stop sign we all know and love, along with the iconic “One Way” and “Railroad Crossing” signs that are still used today.
As the rest of the world caught up to the U.S., the United Nations attempted to get the world on the same page regarding traffic signs, but the U.S. wouldn’t go along. “It turned out that Americans, still riding the intoxicating high of World War II propaganda and American exceptionalism, did not look kindly on European triangles telling them how to drive,” the video says.
In 1968, the Vienna Convention on Road Signs & Signals created a universal road sign system joined by 69 countries, and today, it governs the road signs seen in most of the world. The United States refused to sign the agreement. Why? Half as Interesting cites 3 big reasons.
“Technically, legally, roads are under the purview of the states, not the federal government and so the federal government signing a treaty telling them how to handle their roads is a bit legally murky, the video says.
“Second, at the time of the treaty, the US was working on the Interstate highway system, which they felt would require a lot of breathless, fast-paced innovation in the rough and tumble world of roadside signage and they didn't want to be bogged down by the strictures of a treaty,” the video continues. “Third, given that the US had the most robust driving history in the world, Americans were pretty much their existing signs and they didn't much want them to change.”
If the UN figured out how to tell the British to drive on the other side of the road, Americans could get a rental car in London.
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There's a reason why some people can perfectly copy accents, and others can't
Turns out, there's a neurodivergent link.
A woman in black long sleeve shirt stands in front of mirror.
Have you ever had that friend who goes on vacation for four days to London and comes back with a full-on Queen's English posh accent? "Oooh I left my brolly in the loo," they say, and you respond, "But you're from Colorado!" Well, there are reasons they (and many of us) do that, and usually it's on a pretty subconscious level.
It's called "accent mirroring," and it's actually quite common with people who are neurodivergent, particularly those with ADHD (Attention Deficit Hyperactivity Disorder). According Neurolaunch, the self-described "Free Mental Health Library," "Accent mirroring, also known as accent adaptation or phonetic convergence, is the tendency to unconsciously adopt the accent or speech patterns of those around us. This linguistic chameleon effect is not unique to individuals with ADHD, but it appears to be more pronounced and frequent in this population."
Essentially, when people have conversations, we're constantly "scanning" for information—not just the words we're absorbing, but the inflection and tone. "When we hear an accent, our brains automatically analyze and categorize the phonetic features, prosody, and intonation patterns," writes Neurolaunch. For most, this does result in copying the accent of the person with whom we're speaking. But those with ADHD might be more sensitive to auditory cues. This, "coupled with a reduced ability to filter out or inhibit the impulse to mimic…could potentially explain the increased tendency for accent mirroring."
While the article explains further research is needed, they distinctly state that, "Accent mirroring in individuals with ADHD often manifests as an unconscious mimicry of accents in social situations. This can range from subtle shifts in pronunciation to more noticeable changes in intonation and speech rhythm. For example, a person with ADHD might find themselves unconsciously adopting a Southern drawl when conversing with someone from Texas, even if they’ve never lived in the South themselves."
People are having their say online. On the subreddit r/ADHDWomen, a thread began: "Taking on accents is an ADHD thing?" The OP shares, "My whole life, I've picked up accents. I, myself, never noticed, but everyone around me would be like, 'Why are you talking like that??' It could be after I watched a show or movie with an accent or after I've traveled somewhere with a different accent than my 'normal.'
They continue, "Apparently, I pick it up fast, but it fades out slowly. Today... I'm scrolling Instagram, I watch a reel from a comedian couple (Darcy and Jeremy. IYKYK) about how Darcy (ADHD) picks up accents everywhere they go. It's called ADHD Mirroring??? And it's another way of masking."
(The OP is referring to Darcy Michaels and his husband Jeremy Baer, who are both touring comedians based in Canada.)
Hundreds of people on the Reddit thread alone seem to relate. One comments, "Omfg I've done this my whole life; I'll even pick up on the pauses/spaces when I'm talking to someone who is ESL—but English is my first language lol."
Sometimes, it can be a real issue for those around the chameleon. "I accidentally mimicked a waitress's weird laugh one time. As soon as she was out of earshot, my family started to reprimand me, but I was already like 'oh my god I don’t know why I did that, I feel so bad.'"
Many commenters on TikTok were shocked to find out this can be a sign of ADHD. One jokes, "Omg, yes, at a store the cashier was talking to me and she was French. She's like 'Oh are you French too? No, I'm not lol. I'm very east coast Canada."
And some people just embrace it and make it work for them. "I mirror their words or phrase! I’m 30. I realized I start calling everyone sweetie cause my manager does & I work at coffee shop."