Was This Thing Programmed in England?

One of the side-effects of ubiquitous cell phones is that parents have become Ground Control when their kids head off on road trips. If you're a parent of a teen, or a twenty-something for that matter, you know all about this--the phone rings, and it's the fruit of your loins (or a friend thereof), calling from the middle of nowhere and asking how to get somewhere else. Of course, you are expected to figure out just where in the middle of nowhere said offspring are, and then plot a route to the desired destination. And you do, because you're a Parent and that's what Parents do, even if your "kids" are now grown-up and married and living in another country.

In the search for an uninterrupted night's sleep, many parents have looked for the technological fix, buying the kid a global positioning system (GPS), complete with turn-by-turn directions. But even technology can't solve all problems, as a friend of mine reports.

Seems his son was up in the hinterlands of Wisconsin, following the directions of his GPS, when it suddenly demanded that he make a left turn onto a road marked with a very clear "DO NOT ENTER" sign. He wanted to know whether he should obey the GPS or the sign. Now, at this point I could pause for a dissertation on how the kid's confusion over which to obey is a symptom of how we're becoming Tools of our Toys, but for now I'll put that tirade on hold. I want instead to consider just where the kid was when he got mixed up. Seems he was approaching a diamond-style interchange between the state highway he was on and a limited-access divided highway. Something like the one at right:

He's coming in from the west (which is the left side of the picture) and wants to end up going north on the four-lane. But when the GPS is demanding (quite insistently, or so he says) that he turn left at the first ramp--in other words, it's telling him to go north on the southbound off-ramp, into the southbound lane of the highway.

Which got me to thinking: why would the GPS want to send him down the wrong ramp into the wrong lane in the wrong direction? Is it just stupid? Is it in fact telling him to take the northbound on-ramp that's the other side of the bridge? (To this last, I have the answer: no; the GPS wants him to go north on the southbound ramp. We know this because once he passed the ramp, it started re-plotting his route.) Could it be that the GPS was programmed in England, where people drive on the left side of the road? Or, for that matter, China, where people also drive on the left side, and where most of the consumer electronics in the world are currently being made?

Or, perhaps, reality is even stranger. When the kid got to the other side of the bridge, the GPS again started telling him to turn left, this time onto the northbound on-ramp. This leads to the rather frightening speculation that the GPS really has no concept of which way traffic goes on a road. Which would make sense--the software's really just seeing lines connecting dots, and plotting a minimum-distance path between them. Which is why, on occasion, GPS units tell people to turn onto the wrong line--for instance a railroad track, as in this New York Times story. Or, as in this story from Germany, into a portable toilet. Who knows; maybe the "P" in GPS stands for something other than "positioning"?