Navigation systems in cars are getting more common in new cars delivered in the United States. They have long been popular in Europe and Japan. The systems themselves are getting better and easier to use. A big step was going from CD map storage to DVD storage (probably double-layer DVDs). Some systems even use hard disks for "map" storage these days because those can store even more than DVDs. The disadvantage of a hard disk is that it can't be updated very easily. As it becomes more common to have common destinations, like restaurants and gas stations, stored in the car, updates become important.
I used "map" in quotes above because more modern navigation systems these days also store aerial photos, so you can display a photo view of where you are going in addition to standard maps. That should make it easy to find your destination, shouldn't it?
Some road testers have evaluated older systems and found that occasionally they get you lost. I assume that is less common these days.
In addition to maps and photos, newer systems also have traffic reports integrated into the system, so they can either warn you about traffic on the roads you plan on traveling, or even route you around those obstructions.
But what about those destinations that involve going via really difficult paths? If you just listen to the woman (they are all women aren't they?) tell you where to turn, some destinations can be very difficult to get to. Sure, she never gets mad at you, but sometimes you miss your turn.
One case was related to me by a friend who got a rental car in Washington DC. That can be a difficult city to navigate in, particularly if you are alone as he was. He dutifully programmed his destination into the navigation system while he was in his hotel's parking garage. As he left the garage, the system directed him to turn left at the next intersection. Oops. That was a half block ahead and across four fully jammed lanes of traffic. He missed the turn and ended up going on a much longer tour of DC than he planned -- but he got where he wanted to go.
I have maintained that if I were driving in a European city alone, a navigation system was mandatory. On the other hand, I would rather not drive in European cities because there is never any place to put your car when you get to your destination anyway. But, if you do 
need to drive, there can be some real problems at "difficult" intersections. Autocar magazine published an article with the cooperation of Navteq, the supplier of map disk information, of the most complex intersections in Europe. I've taken their information and show Google maps and satellite photos of their choices.
Their least difficult choice is on M4 just outside Heathrow airport in London. There isn't much to say about it other than it is complex and difficult to navigate if the traffic is heavy. Apparently that is the case rather often. The problem is that there are a lot of tourists going through it coming out of Heathrow (or going in, I guess), so drivers are often confused.
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Another intersection, if you can call it that, is the "Magic roundabout" in Swindon. That's also in England. I've talked about this in my essay on roundabouts in December of 2004.
Supposedly it is really simple to drive through if you are familiar with how to drive on tr
affic circles. Ours in Long Beach is very confusing to some drivers who aren't familiar with the proper etiquette. Autocar predicts, however, that a navigation system might explode if it had to consider how to direct you through this succession of five roundabouts. Navteq didn't comment.
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Moving away from England, there is an "intersection" that is best described by Autocar. "Go to Rome and the soldier's helmets look like dead animals, the pasta like miniaturized bow ties, and the junctions, well, like giant macadamia nuts. This is the Porta San Paolo, at the southernmost tip of Rome's inner ring road. It joins no fewer than seven of Rome's roads together and it could, at any time, be carrying traffic in any one if 12 directions. Evide
ntly Caesar must have lost his compass when he designed this one." Note also that the roads names are poorly marked. Ugh.
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Autocar rates the two worst intersections, however, in Paris. The runner-up is as follows, "This convoluted mess is what might appear on your nav display as you approach the most fear-inspiring junction in Paris, if not the world. Once you have had first-hand experience of the Porte de Bercy, you don't forget it in a hurry. It's where Paris's Peripherique ring road meets the A4 (another A4?!?) autoroute, as well as a couple of minor local roads. When choked with Renault Clios and Peugeot 206es, there are few places anywhere that you wouldn't rathe
r be. The trouble is, getting around the French capital without going past it is an even less welcoming prospect.
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The best -- or is it worst -- intersection is one of the world's most famous. It is the circle around the Arc de Triomphe in Paris. A sum of 11 unmarked roads enter the circle. How does a nav system direct you through this? It almost would be worth the experience of trying it to find out. Autocar says, "The Avenue de la Grande Armée in Paris must be littered with aftermarket navigation systems discarded, presumably broken, after advising their owners to 'take the 11th exit on the right'. And the electronic box would probably have been right... Aesthetically, the Arc de Triomphe beats London's Hanger Lane gyratory hands down, but given its complete absence of road markings, its slippery cobblestone surface and apparently suicidal scooter rid
ers, plus the fact that vehicles coming into it have priority, it is not one for the faint-hearted."
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Are there intersections like this in the United States? Probably none as bad as these. Our cities are more spread out and weren't designed in the middle ages. We are beginning to experiment with traffic circles, though. West Hollywood tried some mini-circles, but those were quickly abandoned for some reason. Car and Driver reports that a municipality north of Ann Arbor, Michigan, has installed a multiple-traffic circle experiment just off U.S. 23. While the John Phillips reports multiple traffic circles going east away from the main circle shown in the photo, they don't appear on the map or the photo. I guess the map and satellite photo from Google are too old for that. You can read about John driving around the circles and talking to the local police chief in the March 2007 issue of the magazine. It is not on their web site.
Do you have a candidate for "worst intersection for a navigation system" in the United States? Let me know and I will publish the results.
