For a long time, cars had no passenger side mirrors.
I have seen vintage cars from the 60s, 70s and 80s with plane mirrors on the passenger side.
My first car, a Honda Civic bought in 1993 had no passenger side mirror. It was an option at extra cost.
Our first family cars were station wagons bought in the 1970s (from AMC) and mid 80s (from Ford). They had no passenger side mirrors.

When were convex mirrors first used on the passenger side?

Obviously there had to be an adaptation period with automobile manufacturers and dealerships, government highway traffic acts and laws, etc... Drivers also had to get used to these new convex mirrors which could cause a lot of accidents if people didn't realize that objects in the mirror are closer than they appear.
When did convex mirrors become legal and when were the words "Objects in mirror may be closer than they appear" first written on passenger side mirrors.
Also, why did the words use to say "Objects in mirror may be closer than they appear" .
Why the "may be"? Convex mirrors always make objects look further anyway. Plane mirrors give you the real distance.

Now it says "Objects in mirror are closer than they appear" which makes a lot more sense since convex mirrors always make objects look smaller and therefore they look like they are further away.

Thank you.

I first noticed the convex passenger side mirror on one of my father's cars that he bought when I was a kid. Maybe a '78 Pontiac? I'm not sure.

According to this post, the standard took effect in 1971, although there must have been a grace period, because my 1974 Porsche doesn't have a passenger side mirror. And I seem to recall throughout the '70s that passenger side mirrors were options, usually included as part of an appearance package on lower-spec cars, whereas high-cost cars like MBs and Cadillacs had them standard. Also, my 1980 911 has a flat mirror on the passenger side with no warning message.

I don't think objects looking farther than they are isn't really an issue because your brain is able to quickly process the whole image and compensate. Kind of like when you watch TV, your brain doesn't interpret the people as being only a few inches high. If anything, I have to remind myself when driving the '80 911 that the mirror isn't showing me a wide angle. As a result, I find that mirror much less useful than a convex mirror.

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1974 Porsche 914 | 1980 Porsche 911SC
2002 Porsche 911 | 2002 Mitsubishi Montero | 2011 VW Golf

Interesting question. My 1976 Cosworth Vega has dual "sport mirrors" (painted body color, black) but the OE RH lens was flat. It was basically useless with such a narrow field of view.

Of course, Vega production ceased after 1977, but at some point I learned that Monzas and their other division clones with sport mirrors had convex lens, so circa early to mid-eighties on a trip to a Pick-a-Part I found a Monza and removed the right side convex mirror and installed it in my RH CV sport mirror housing. Wow, what a difference!

My '72 Vega GT did not have a RH mirror, and I don't recall it was an option.

At some point dual outside mirrors with a "wide angle" RH lens probably became a NHTSA standard, but I'm not sure of the exact date... probably late seventies to early eighties.

Wasn't it in the last year of two that rear view cameras are required in all new cars?

Speaking of mirrors, I think "folding mirrors" first became a European standard to protect pedistrians and was eventually picked up in the USA and probably became a NHTSA standard. Of course, nowadays most are powered to fold/unfold at the tap of a swtich, but they still fold back if they hit something.

What about those Japanese cars with the dual mirrors out at near the front of the fenders. Is that still a requirement in Japan? I can't imagine they're worth a damn!

Duke