Once heard an anecdote that sounds possible, if unlikely. Was wondering if anybody could verify it, or had even heard of it:
There was a ruler of a land who hated the Western world so much that he decided he wasn’t going to do anything the “Western” way. In the interested of this, they decided to use different colors to denote “stop”, “slow”, and “go” in their traffic lights. I don’t remember the color they chose for “stop”, but it wasn’t red.
They soon started to notice a rise in traffic accidents at intersections, particularly around dawn/dusk and in inclement weather. As it turns out, “stop” lights are red because red has the longest wavelength of visible light, and therefore the most penetrating power of any color. They then had to grudgingly admit that not all Western ideas are bad.
My questions:
Is that really why red means both “stop” and “emergency exit”?
And is this anecdote true? If so, what country was it?
Why not? Red light does have the longest wavelength of visible light. Whether or not that contributes to its purported penetrating power or not, I can’t say without a bit of research, but that’s not what you said.
Arggh, I don’t know what I was thinking. Red light does have the longest wavelength. But I doubt that was a major consideration, considering that the use of red lights goes back to before that was determined.
“Red, the color of blood, has been a danger signal since time immemorial. It’s said the Roman legions bore the red banner of the war god Mars into battle 2,000 years ago.”
The story doesn’t make much sense to me. If they noticed an increase in accident, that must mean that they had conventional traffic lights at first and one day they decided to change the rules. Of course there would be more accidents! Nobody would attribute that to the lesser penetrating power of blue light.
Although emergency exit signs are usually green outside the US…
Don’t know. I remember in some of the HMS Titanic transcripts that someone aboard the Californian said that (in reference to the unidentified ship they saw in the distance) “We first saw red, then green.” Or maybe it was the other way around. The point was, they saw the ship making a turn.
Red and green lights identify port (left) and starboard (right) on a ship respectively.
When two ships approach each other head-on, the rule is that they always “pass to port” - i.e. each leaves the other ship to their port side (thus, steer to the right).
Buoys with red and green lights indicate which side you are to pass them on (usually to keep your ship in a channel or shipping lane). A red buoy indicates you pass to port; a green one indicates you pass to starboard.
Green buoys to indicate port were a development in the past twenty years; when I was growing up, a black buoy mean pass to port (when returning). At some point, black buoys were painted green because it was easier to see in dim light.
The red/green lights, however, are considerably older.
That, of course, depends on whether you’re entering the harbor or leaving it. The general mnemonic is “red right returning,” so you pass red buoys to starboard when entering the harbor.
The choice of red is traditional, not scientific. A study back in the 60s indicated that red was hardest of all colors to judge diminishing distances with. There was a suggestion that taillights be made a different color so people could judge distance better, but it went nowhere.
There’s an excellent history of signal light colors in Marvin Harris’ book Cultural Materialism. As Harris points out, red is not the universal color for “stop” or “danger”. For a time, railroad signals used blue or even green to indicate “stop”. The choice of colors is arbitrary and has become ingrained through long usage, not because of the physical properties of the lights or relationship to spectra. If anything like the OP ever happened anywhere, I’d bet it was because people were used to stopping at red and going on green, and simply lapse back to old habits.
Red may be arbitrary among humans, but most poisonous insects and amphibians tend to be red, yellow or orange, and predators seem to instinctively know this. Moreover, humans appear to have an instinctive fear of certain critters as well–snakes and spiders are probably the most oft-cited examples.
It seems plausible to me that humans may have some sort of instinctual reaction to the color red as well.
I agree the story is probably completely spurious, but I do vaguely remember a couple of things: In some scientific study, babies left in a room with the walls painted blue or yellow cried considerably less than babies left in a room with the walls painted red. I think other colors were tested too, but I don’t remember much of the specifics. Another thing I’m pretty sure I heard somewhere was that traffic lights have been developed to be a certain type or shade of red and green so that people with red/green colorblindness can tell them apart.