One school of thought says that SUV buyers harbor a kind of outdoorsy fantasy. But I suspect that it's more basic than that: this is a vehicle that can flourish in the most extreme environment imaginable. If it can ford streams and climb over boulders, just think how safe and protected you'll be on the trip to Wal-Mart! Of course, the logic behind that argument is backward: the trip to Wal-Mart is a good deal more hazardous than fording a stream in the wilderness, and we ought to be buying cars optimized for the conditions we actually drive in.

Well, it's not quite what people said about sports cars: for example, I think the people who buy sports cars have excessive confidence in their driving skills. But, in general, the more expensive an item becomes, the more psychological factors play into the purchase decision.

There's a television commercial for an SUV in which a woman is driving the SUV and a rock rolls onto the road in front of her, and she swerves around it at the last minute. That ad claims that SUVs are nimble, and suggests that the key variable in avoiding the rock was the vehicle. That is an attempt, it seems to me, to play to the driver who lacks confidence in his or her skills. The most dominant image in SUV commercials and ads is still the SUV mastering some off-road obstacle: fording streams, cutting through snowbanks, racing across virgin wilderness. Obviously, almost no SUV driver is ever going to use his or her car in those environments (in large part, of course, because racing across virgin wilderness in an SUV is, for the most part, illegal). Another interesting thing about SUV advertisements, along these lines, is how rarely children appear in them. Keith Bradsher makes this point in his book, High and Mighty. Minivans are advertised in family-centric ways. The SUV, on the other hand, is supposed to allow the buyer to pretend that he or she doesn't have a family, that he or she is still a kind of rugged loner without suburban entrapments.

If every car on the road was a Mini, then the cost of an accident would be quite small: if you are in a Mini and you hit a Mini, you aren't going to be that bad off. So, in the old days, the premium on active safety wasn't so large. On the other hand, if every car on the road is an SUV, the cost of an accident grows substantially. When a Ford Explorer hits a Chevy TrailBlazer, both parties suffer enormously. And, if a Ford Explorer hits a Mini, the Mini driver is a dead man. ... As a non-SUV owner, I simply cannot afford to get into any accident at all these days.

I don't think we can easily cure people of their desire to feel safe - even if that desire does not correlate with actual safety. But what we can do - and ought to do - is limit the damage that that obsession does to others. The important thing to remember is that the harm that SUVs do to other vehicles is not a simple function of their excessive weight. In other words, if a five-thousand-pound SUV hits you, you aren't automatically dead. Cars are so beautifully designed these days that they can safely absorb tremendous forces in an accident. (I always think of the fact that the bodyguard in the front seat of Princess Diana's Mercedes survived that crash, which was into a concrete pillar reportedly at a speed in excess of ninety miles per hour. That's how good car safety has become.) But all those safety mechanisms usually work if the car is hit squarely (or, at least, on the same plane) by the opposing vehicle. That's what is not happening now. SUVs are so tall that cars simply submarine them. The kind of redesign that the automakers are talking about - making SUVs less "aggressive" in their accident posture and reducing the risks of that kind of submarining - is critically important. Of course, it would be better if every car on the road was the same weight. But that's not going to happen.