According to Ogden Nash, the buses to Scranton travel in pairs, but at UCSC, according to Geoff Pullum, the buses travel in loops. As you might expect, roughly half of the buses that circumvolve the campus are deasil buses, and the other half are withershins buses. What bothers Geoff is the way in which these routes are labelled:
On the shuttle buses is a sign warning cyclists that the crucial bike racks on the fronts of the buses are found "only on westbound Loop shuttles."
What in heaven's name can they mean? [...] The idea that you can distinguish a clockwise from a counter-clockwise circular loop by saying that one goes to the west and the other doesn't is not just wrong, it's a screamingly obvious geometrical impossibility.
Mark Liberman riffs on this in the erudite manner you might expect, pointing out a few other cases in which conventional or official direction names utterly fail to correspond to geographical reality, and he even brings all this back to linguistics by proposing an analogy with the structuralist phonology of Jakobson and Trubetzkoy. (By the way, there are more conflicting road signs where the one to the left came from, although there doesn't seem to be an example of the four-directional holy grail.)
What I'd like to do, though, is point out that it is not a "geometrical impossibility" to describe a loop as "westbound." It happens to be a geographical impossibility at UCSC, but that's just a consequence of the location of the campus.
From the PDF files of the bus maps, it seems likely that, at UCSC, "westbound" means "withershins." I say this because the other bus route shown in the PDF file travels an irregular but non-loopy east-west path, which overlaps the loop route, and it's headed west when its path coincides with that of the counter-clockwise loop bus. That means that all we need to do to make sense of the "westbound" designation is to assume that the Music Center is at the South Pole.1 Voilà: clockwise == east, and counter-clockwise == west. The assumption is false, of course, but, after all, the magnetic poles of the Earth move around a bit (last I looked, magnetic north was somewhere in the vicinity of Bathurst Island), and so we use arbitrarily designated stand-ins, for the useful purpose of making our parallels of latitude stay put when we navigate. Many cities have a notional "north" that's aligned with their street grids but a few degrees off of true north; we just need to say that UCSC has a notional "south" that points this way. Or, if truth in bus-route designations is paramount, the obvious solution is to move the campus to Antarctica.
Update: In a followup post entitled "Loopy defenses of the shuttle bus sign," Geoff Pullum reports that Fernando Pereira offers a (more topologically sophisticated) demonstration that there can be such a thing as a "westbound" loop. (I don't mind having been trumped in geekiness; I'm still unreasonably pleased with myself for having been able to use the phrase deasil buses in the first pararaph of this post.)
1. Or, if I'm wrong about which way is "westbound," the North Pole. (This alternative might lead to the use of Santa Cruz as an eggcorn for Santa Claus.)
