Color blindness and stoplights

During a tiresome wedding reception this weekend I learned a guy I know is colorblind. He said he has can’t discern the difference between red and green. Only later, during the ride home did it occur to me…

How do you know wheather or not the stoplight is red or green?

And don’t give me that “They must know from wheather its the top or bottom light lit” because I owned the same car for eight years and never did manage to remember which side the gas tank was on.


The green light is the one on the bottom.

Life is short. Make fun of it.

Are you sure…?

Golly, I sure hope so.

I had a freind w/ this type of color blindness. He used the “green light on the bottom” method, but said that he also had to be more aware of what other drivers (on his street as well as cross traffic) were doing wrt signal lights.

It’s very very rare for Red-Green colour blindness to be so severe as to totally eliminate red and green from someone’s vision. Usually it’s just that you find some colours hard to define clearly as either reddish or greenish.

Anyway, anyone with any sort of disability, be it minor or major, learns to compensate. They figure out different ways to know what’s what. Same applies here.

“So what you are telling me, Percy, is that something you have never seen is slightly less blue than something else that you have never seen.”

My resident expert, my husband, is red-green color blind. He says to him the green light looks white while the red has some color.

A green stoplight ( or should it be called a golight) is designed to emit blue light along with the green. In Japan, the first traffic lights were actually colored red, yellow, and blue. They have been changed to adhere with international standards, The common expression is still ‘Hey the light is blue! what are you waiting for’

Ink - do you manage to remember which color means stop and which means go and which means “floor it”? I thought so. As others have pointed out, the similar association of top = red is all the information a severely color-blind person needs.

One of our humble associates here at the Straight Dope has an acquiantance who was so badly color blind he wore sickly green suits for years, thinking them gray. The intervention was successful.

I suffer the same problem ('cept, it’s called “Color perception deficency” YAY!! I have my own euphemism!!). I had a '74 VW Beetle that was Forest Green and LOOKED green to me, but the interior was a lighter shade of green that looked gray to me. Most reds and greens, if they’re dark enough, look right, but colors CONTAINING red or green (ie. purple) give me problems. It got to a point that when I shopped for clothes, I only bought clothes with the color printed on the tag! So, I ended up with a LOT of navy blue and khaki pants and shirts (of course, you can’t go wrong with white shirts).

When people find out about my “condition”, the first they say is “Hey, what color is this”.

…the hell?

Trump: you should use my method of shopping for clothes. I’m severely colour-blind also so when I go clothes shopping, I ask one of the female sales associates (two reasons: 1) females are less susceptible to colour-blindness & 2) males don’t like to admit their deficienceis usually) to assist me & I tell her about my visual condition.

My girl-friend also helped by buying me socks with little logos sewn into the top. Different colour, different logo. I select socks with matching logos.

I knew someone in high school who was red-green colorblind. He said that if you put something red next to something green, he could tell that they were different colors but not which color they were.

He used the ‘red-on-top’ method of dealing with traffic lights. However, an intersection in a nearby town had a very old traffic light that was backwards - red-on-bottom - and the first time he drove thru it he got a ticket. He avoided that intersection whenever possible, until the town finally put in a modern traffic light.

Just FYI, pilots and boat captains cannot be colorblind because so much of navigation depends on determining red from green! Well, maybe they can be blue-yellow colorblind, but definitely not red-green colorblind.

I have as much authority as the Pope; I just don’t have as many people who believe it! - George Carlin

Note, too, that if the light is sideways, the red is left, the green is right.

A motorist in most states must know the direction of a standard traffic signal to pass the test for a lisence.

My father is colorblind. Stoplights can have their colors arranged anywhich way so it is up to states or municipalities to regulate them. I remember Dad approaching our legislator to try to get legislation passed years ago to make it manditory to make the lights a set pattern so that colorblind individuals could distinguish between the red and green.

Where I come from (Quebec) all the street lights have a shape associated with the colour:

red = square,
yellow = diamond,
green = circle.

The lights are arranged horizontally: two reds, one at each extremity and the yellow and the green in the middle. I thought everyone had the same system. It makes it very clear for colour-blind people.

For me the confusion is not red vs. green, but green vs. halogen street lamp. When driving at night through a busy intersection where there are many light posts, it is mighty hard to discern the “go” light from the row of street lamps.

My personal anecdote of being colorblind: In 4th grade art class, I made a ceramic frog and painted it brown. Teacher asked if I thought that frogs were brown… my response was no, I thought the brown paint was green. Also I used to wonder why people always said grass was green, when it clearly was a pale orange.

“Where there is clarity, there is no choice. And where there is choice, there is misery. But then, why should I speak, since I know nothing?”

I am red-green blind and the colors on stoplights do not even begin to look the same. I don’t know how it is for people with more severe color blindness, but in my case bright apple green and bright cherry red are nothing alike. It’s only with dull muddy colors that things get confusing. Brownish green and brownish red are not very discernable from each other, as both look brown, same goes for greyish colors and ordinary shades of red and green in bad lighting conditions. I think of lot of color perception has to do with what you learn a thing is supposed to be also. Grass looks green to me, but perhaps if I saw grass that was grey I would still think it was green? I’ll have to check this out.

Montys given me a great money making scheme!

Geranimals for the colorblind!

Remember Geranimals? Heavily advertised during Capt’n Kangaroo in the seventies?

They were a line of childrens clothes with animal tags, and you matched, say, tiger pants with tiger shirts, and that was a fashionable (for the sevinties at least) match. Basically they were for fashion retarded fathers stuck with clothes shopping duty (don’t believe your dad was a fashion retard in the seventies? Get that photo album out! Denim, denim, denim!)…


I remember when I was a kid they had sideways-mounted stoplights in Columbia, MD. Architecturally distinctive (so Mr. Rouse was happy) but I suppose the DOT ordered them replaced with more conventional ones.

When I worked for Lenscrafters ages ago, in the lab there was a techinican that usually worked the finish side of the lab, and often put the tints on lenses. The tints were in little metal bins, at around 240 degrees, and weren’t labeled, as they were usually strongly colored.

He worked there for some time, apparently, before letting everyone know he was completely color-blind. Everything was black and white to him, and he had learned through trial and error which tint was what. He’d done the same thing with the lens blank packaging, which was color-coded.