The risks versus the improvements of GPS-based navigation

I found this recently while reading Risks Forum Digest, issue 25.86, to which I have been a subscriber in some form for most of a decade (I used to read via the comp.risks newsgroup, but haven’t bothered with Usenet in some time). This particular item was submitted by Jerry Leichter and is a well-written defense of GPS technology. I thought I’d share some of it and add some of my thoughts on the matter as well, being a technology admirer myself.

Subject: Re: The Joy of satellite navigation failures

In RISKS-25.85, Steve Loughran complains specifically about an ad in which a car will use GPS “to get you home” – and more generally about over-reliance on GPS.

I find myself increasingly an old curmudgeon myself, and I’m bothered by the young whippersnappers who couldn’t read a map to find their way down a midwestern plains highway – dead straight and level as far as the eye can see in both directions.

And I’m sure the new old curmudgeons of 2029 will probably find themselves equally bothered by the young whippersnappers that probably couldn’t operate an “old school GPS” to save their lives. I dare not speculate on what technological advances will come our way in the next two decades. Such is the advance of technology; I remember taking a typing class with a real typewriter in high school, after our one required semester of “computer literacy” in middle school. (In a way I am glad that typewriters are still being made as there are uses for them. But they are nothing like the typewriters of even 1989.)

But … let’s be a bit objective here. How accurate were paper maps? The period in which, even in the US and Western Europe, you could rely on maps to be more than approximations doesn’t date back much more then 50 years or so. (…) Are GPS maps up to date? How about the paper maps that used to fill glove boxes?

There are cases where GPS maps won’t be as up to date; see an article at However errors in paper maps can be just as bad, and in some cases even worse.

Our local cartography company, Key Maps, is the “gold standard” of local maps, and I learned from my former experience as a courier that frequently the maps for surrounding counties (in addition to the Houston-Harris County map, they also publish editions for Brazoria & Galveston County, Montgomery County, and Fort Bend County) contain errors and inaccuracies or at the very least didn’t match what the city or county actually posted on the road signs (or in at least one case when I ran a delivery to an unincorporated part of Brazoria County, whether a sign was posted to identify the road at all).

Even national cartographers aren’t immune from slip-ups. If nothing else, toll roads that have had tolls removed may still be listed as toll roads for years after the removal.

Accurate road markers are of roughly the same vintage – and for historical reasons are often difficult to use for navigation. When I drove in England about 20 years ago, most road signs except on the largest roads (a) did not show you the compass direction; (b) named the next town down the road, not some larger city you might have heard of beyond that. One wrong turn and you could go many miles the wrong way without knowing it. (I did!)

Indeed, this is a rather large risk in and of itself, but I’d say this is more of the fault of the local road authorities for not adopting a system of control cities in the fashion of the US. For the non-roadgeeks, a control city is one posted on the road signs to indicate where a highway goes, and is usually but not always a major city. (As an example, from Houston, the nearest control cities are San Antonio (I-10 west), Austin (US 290), Victoria (US 59 south), Galveston (I-45 south), Beaumont (I-10 east), Dallas (I-45 north), and Cleveland (US 59 north; note this is the small town past Kingwood, not the one in Ohio). Houston itself is the control city for destinations going the other direction from the aforementioned control cities.)

Of course, the compass directions posted on road signs are often the subject of jokes when a road that is posted “south” actually runs north from the sign, but that’s another rant for another day.

The fact is, GPS’s get it right most of the time. They are much easier to use, much more reliable (when you consider the entire system, including the inexperienced map reader), much more accurate than any system we had before. People aren’t going back, short of some kind of collapse that renders the systems inoperable. There’s not much point in complaining.

Indeed, I would not voluntarily quit using a GPS unit if I had one. I found myself wishing for a GPS at several points during my time as a courier, especially going outside the area covered by the Houston-Harris County Key Map.

Do inappropriately used or badly designed GPS’s cause problems? Sure, but just how new are those? People blindly followed maps, too – sometimes because the maps were wrong or simply omitted some information like “low bridge” (frankly, I’ve never seen a consumer road map with that piece of information on it, any more than consumer GPS’s inappropriately used by truckers show this information), sometimes because most people never learned how to read more than the basic information from a map.

I remember we were required to learn map reading in school, I think as part of our social studies classes. Really, to think about it in depth, both how to read a road map and use a GPS should be taught as part of driver’s education. (Make no mistake about it, we will have paper maps for some time yet to come.) This would help the chaos currently prevalent on the roads more than one might otherwise think.

We can certainly make the current systems better – and we are. But consider: Suppose you were driving somewhere unfamiliar, in a heavy thunderstorm, using your GPS – and I suddenly took it away from you and handed you some 4-year-old ratty, disintegrating map out of the glove box. Would you think I’d improved things for you?

And this is the point that many people miss when they choose not to trust a GPS and rely instead on paper maps or (sometimes) printouts or directions from an online mapping service such as Mapquest or Google Maps. Granted, there are cases where the GPS gets it horribly wrong, but overall it’s an improvement over the “old school” method of paper maps.

2 thoughts on “The risks versus the improvements of GPS-based navigation”

  1. If you go back to initial posting:… you can see that map failure modes are one of the problems, there being others. What I worry about is the fact that this was a BMW advert saying "GPS will get you home" without any small print like "use some thought rather than blindly following GPS down a mountain footpath".

    Paper maps have their own failure modes too: you cant download updates, you can't press a button to see it rendered from a different viewpoint, you can't get a trace of where you went. And they are cluttered with stuff (legal boundaries and such like) that distract you. But is having a car issue commands "turn right" that much better?

    My recent post International Persecution

    1. I would call those "failure modes" limitations of the medium.

      I do admit we will have paper maps for some time to come. I would never completely depend on GPS; if it misbehaves badly enough, there does come a time to shut the thing off and look at a paper map.

      The saying "common sense isn't so common anymore" used to be kind of funny, but with people following GPS directions onto train tracks and the like, it's been proven frighteningly accurate.

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