October 06, 2004

Un système où tout se tient, and east is west

Geoff Pullum has described a campus bus loop where counterclockwise buses are called "westbound" and clockwise ones "eastbound", or maybe vice versa, he's not sure. The uncertainty bothers him. But I can tell you that it's not always a comfort to know.

I'm now sitting just below the "r' in "Spruce St." in the map fragment on your right, about a half mile west of Interstate 76. Nobody around here calls it I-76, though -- it's the Schuylkill (pronounced "skookle") Expressway. Since north is up as usual, you can plainly see that the Schuylkill runs from southwest to northeast through this section of Philadelphia. Reasonably enough, some of the local access signs even offer you a choice between the "north" and "south" directions, with "north" here meaning "northeast". But even-numbered routes in the U.S. are east-west routes, logically speaking, and I-76 was at some point nominally amalgamated with the Pennsylvania Turnpike, which runs east-west through the state. Though I don't know the political history, my guess is that this had something to do who pays for what. Anyhow, to maintain consistency with the rest of I-76, if you leave Penn in a geographically northeastern direction, the official signs tell you that you're going "west", while if you head in a geographically southwestern orientation, you're officially going "east".

More complex versions of this problem afflict the ring roads that partially or completely encircle many American cities. You'd think that on a circular road, the signs would say things like "Clockwise to Braintree" or "Counterclockwise to Silver Spring", but not so. Instead, compass directions seem to be assigned by some random and historically unstable mixture of local tradition, true geographical orientation, continuity considerations and even-odd number-direction parity.

This reminds me of a story that Roman Jakobson liked to tell. It seems that a certain African culture used "talking drums", with the traditional mapping of syllable count and timing onto drumbeats, using high and low pitched strokes for syllables with high and low lexical tone, respectively. Messages from the center of the village were sent by drumming on a large hollow log, one side of which sounded a low-pitched note while the other sounded a higher pitch. But then the log cracked, with the result that striking the previously lower-pitched part now actually yielded a higher pitch than the other part. What did the drummers do? Well, they went on drumming as before, except that now linguistic high tones mapped onto a lower-pitched drum sound, while linguistic low tones mapped onto a higher-pitched drum sound.

Jakobson liked this story because it illustrates the structuralist prejudice that it's only the system of contrasts that matters, not the content. But I'm almost certain that the story was false, all the same. Not the talking drum part, that sort of of thing was and is widespread in Africa. The thing is, though, if a drum had broken, I'll bet that the drummers would have fixed it or replaced it, or at worst turned it around.

Here in the U.S., we're not so sensible. The federal and state departments of transportation are hotbeds of unreconstructed structuralists. A road only goes two ways, right? All integers are even or odd, right? A plane surface, or the surface of a sphere, is two dimensional, right? Do you see where this is going? I mean, this is a system of oppositions! Clockwise/counterclockwise, east/west, north/south, even/odd, what's the difference? You're fretting about mere implementation details.

Roman Jakobson's good friend, that arch-structuralist aristocrat Nikolai Sergeevich Trubetzkoy, famously said that phonetics is to phonology as numismatics is to economics. Well, I'm a phonetician, myself, and it bothers me every time I drive northeast on I-76 West.

[Update: Emily Bender emails to point out that they do everything on a grander scale in California, even confusion:

I can beat your driving northeast on I-76 West story, by a bit: In the San Francisco Bay Area, there is as stretch of road that is both I-580 East and I-80 West (in one direction) and I-580 West and I-80 East (in the other). It actually runs North-South, of course.

(To locals, it would never be called I-580 or I-80, though. Just 580 or 80.)

Again, I blame the structuralists.


[And in defense of the midwestern forces of disorder, Daniel Drucker emailed a pointer to this picture of a north-south road segment (near Burlingame, Kansas) which is simultaneously 56 East and 31 West (or the other way around in the other direction, of course). He also diagrams the road graph that gives rise to this state of affairs:

<- 31 W _____ _____ 56 E ->
<- 56 W _____|_____ 31 E ->

I believe that I've seen clusters of road signs that encompass three of the four compass directions at once for the same stretch of road, though I can't cite an exact reference much less provide a picture. Has anyone seen a cluster that covers all four compass directions? That would be something to treasure, like the legendary intersection where four one-way streets converge, all pointing inwards. ]

[Update: Q_pheevr introduces some nifty terminology, and a picture of a three-direction road-sign cluster (421 north, 66 south, 80 west). Q even points to a picture of a four-direction cluster, from Kentucky -- but it's at an intersection, which is cheating. I'm still waiting for a cluster in which routes nominally in all four compass directions are oriented in the same physical direction on the same stretch of physical highway. This is clearly a graph-theoretic possibility, and I'm betting it happens a few times across this great land of ours.]

[Update 10/8/2004: Joshua Guenter (Editor of Pronunciation at Merriam-Webster) emailed that

There is, believe it or not, a single example of cardinal direction-sensitive highway numbering in the United States. I refer to U.S. Highway 101, which runs most of the length of the Pacific Coast. From Los Angeles to around Beaver, Washington, it's labeled pretty much what you expect of highways: North or South, regardless of what cardinal direction one may be actually heading in at the time. The thing is, though, it begins to loop around the Olympic National Park in Washington, first going east, then going South to Olympia. If this highway kept the same directional labeling system of all other highways, you'd soon find yourself going South on 101 North for about 90 miles. I guess this was just too much, so the west-east section of 101 to the north of Olympic National Park is actually labeled 101 West and East while the section to the east of Olympic National Park between Gardiner and Olympia is re-labeled 101 North and South, but corresponding to the cardinal directions.

In other words, if one drove from Los Angeles to Olympia, never leaving U.S. 101, you'd be first on 101 North (for quite a bit), then on 101 East, then on 101 South, all the time staying on the same road. This is the only example of this I know. Maybe there are others?



Posted by Mark Liberman at October 6, 2004 11:10 PM