Traffic sign shape meaning: more sides = more danger?

[Dustin DeWinn]

I've heard this a few times and was curious about it's validity. What do you guys think?

Here's one site of many: http://mentalfloss.com/article/56877/why-do-stop-signs-have-eight-sides

I know that traffic signs have different shapes and colors to communicate varying levels of danger and genres of information so that even if the sign was unreadable or seen from behind, you could at least tell from it's shape what type of sign it was.

However, I've read that the shape itself indicates a level of danger; more sides more danger. Square and diamonds are one, Pentagons are another, Octagons, then circles for Railroad crossings.

I know Yield has the least number and seems just as dangerous as a stop sign if not adhered to, but I wanted your thoughts on this.

Thanks

[adventurernumber1]

I'm not sure. I might think that warning signs would be those that signal the most danger (after all, they are warning you of something coming up, such as the risk of wild animals (deer, moose, etc.) crossing the road, steep grades, a very twisty upcoming section of road, a slippery road, and more). Of course, warning signs are in the shape of a diamond (which has four sides), and are yellow. It is a neat theory, but I doubt that it is actually true, since warning signs may typically signal the most danger.

[oscar]

Circles (for RR crossings) have no sides, yet indicate serious potential danger.

Rectangles, squares, or pentagons are often for route markers, or other things that aren't warnings at all except for pentagon school zone warnings.

I don't see much correlation between the number of sides and the level of danger.

[Dustin DeWinn]

Sorry, hyperlink fail. The mental floss link should now be correct.

[djlynch]

Circles (for RR crossings) have no sides, yet indicate serious potential danger.

To a mathematician, a circle is a regular polygon with an infinite number of sides.

[Super Mateo]

I don't buy this either.  The "No Passing Zone" pennants only have three sides, and they warn drivers of dangerous places to pass.

The Railroad sign may have a debatable number of sides (which I'd say is 1), but the crossbucks have 12 (if they're a single piece) and they indicate that a track is right there.

The amount of danger is subjective.  It's a tough thing to quantify.

[adventurernumber1]

And about the railroad sign, and circles in general, the number of sides is indeed debatable. I personally consider a circle to have an infinite number of sides (and that is what went through my head as I read the OP of this thread), but it could also be argued that circles have 0 or 1 sides. Either way, I do still doubt the validity of this theory, even though it is quite interesting to think about.

[DaBigE]

I don't buy this either.  The "No Passing Zone" pennants only have three sides, and they warn drivers of dangerous places to pass.

Agree. Could also add Do Not Enter (US-style) and Wrong Way signs to the highly dangerous list as well.

[jeffandnicole]

No Parking signs are rarely posted as a 'danger' yet have the same number of sides as most other signage.

And what's the danger in a 4 sided sign showing lane movements?

[Mr. Matté]

Circles (for RR crossings) have no sides, yet indicate serious potential danger.

To a mathematician, a circle is a regular polygon with an infinite number of sides.

Interstate and California route shields also have infinite sides (based on their all-curved sign cuts) so ∴ railroad danger == Interstate danger == CA Route danger.

[Scott5114]

I've heard the idea before, and pretty much figured it was bunk, but the idea of ascending number of sides meaning something seemed pretty interesting.

Based on this, at work, I've adopted the practice of putting the batch number on a set of processed tickets inside a shape, with ascending number of sides on each batch. Batch #1 of the day is a triangle, #2 is a square, #3 is a pentagon, #4 is a hexagon. In the uncommon event we get to #5, it's an octagon, because I really want to stop by then! #6 and on are all circles because by that point I would be so worn out I couldn't care less about the number of sides...

[paulthemapguy]

Circles (for RR crossings) have no sides, yet indicate serious potential danger.

To a mathematician, a circle is a regular polygon with an infinite number of sides.

No.  A circle is not a polygon to a mathematician.  But I see your point.  This theory proposed in the mental floss article is clearly from someone who thinks a lot about math and not so much about traffic.  The theory makes me chuckle a little bit.  Like lol no.  I'm a fan of mathematics myself but I know that the overwhelming majority of people aren't thinking of geometric theories when they look at road signs.  The reasons for sign shapes are probably based more on the psychology of common people and what symbology they believe warrants a heightened amount of attention.

I would assume that cutting straight lines is easier than cutting a curve adherent to a certain radius.  I'd postulate that a manufacturing constraint would be much more likely to birth the octagonal shape, compared to some theory of infinite sides to a circle.  I'd imagine that a diamond would attract more attention than a typical rectangle, since we just don't see as many diamonds in our everyday lives compared to rectangles.  That's probably why warning signs are diamonds rather than rectangles.

[vdeane]

When deciding if circles have infinite sides or not, I usually just defer to Flatland.

[kphoger]

To a mathematician, a circle is a regular polygon with an infinite number of sides.

Not necessarily.  Different mathematicians have different opinions on the number of sides a circle has.  One common answer is that a circle has two sides:  the inside and the outside.  A good friend of mine who has majored in math for several years holds this opinion, FWIW.

[CtrlAltDel]

According to H. Gene Hawkins, Jr., who has written extensively on the history of traffic control devices, the Mental Floss article is largely correct, or at least it was back in the day. As he states in "Evolution of the MUTCD Part 1: Early Standards for Traffic Control Devices" :

The first effort to establish a basis for uniformity in signing and marking took place in the fall of 1922, when W.F. Rosenwald of Minnesota, J.T. Donaghey of Wisconsin, and A.H. Hinkle of lndiana made a trip through several states to try to work out some uniformity or standardization in the marking and signing of highways. Their findings were reported at the 1923 annual meeting of the Mississippi Valley Association of State Highway Departments (MVASHD). That body agreed on a signing plan that used distinctive shapes for different danger conditions–the same sign shapes in use today.
   The progression in shapes from a circle to a square was intended to indicate increasing levels of danger. Round and octagonal shapes were selected to indicate the most danger because they required the most cutting and wastage, and they would also have the fewest number of installations.

Accompanying is the following diagram:


His web site, which hosts a link to the article is here: https://ceprofs.civil.tamu.edu/ghawkins/mutcd-history.htm