We have been quite happy with our most recent car, a Pontiac Vibe (aka “Toyota Matrix”). It gets reasonable mileage; comfortably seats two adults, a dog, and a toddler (along with all of the attendant stuff); and has been painless to maintain. One of the best things about the Vibe, though, is that it is a remarkably well-designed car. Here I refer not only to the main user interface—which places necessary functionality within reach of the driver, labeled unambiguously—but also to the layout of the car’s interior.
The only design complaint I have with the Vibe relates to the headlights, which turn on automatically at dusk. (They can also be turned on manually.) This seems to me to be a worse design choice than either obvious alternative: namely, all-manual headlamp adjustment or always-on headlamps (perhaps with a “manual off” option). I think this is the case because it tries to be too clever and fails.
The situations that demand headlamp use are fairly common, including darkness, overcast weather, and precipitation. By contrast, situations that contraindicate headlamp use are rarer: very dense fog comes to mind, but I can’t think of many others. In a car with always-on headlamps, one only has to worry about the rare case: how to disable the headlamps when their use makes the situation worse. In a car with fully-manual headlamps, one only has to worry about the common case. (In practice, I’ve found quickly develop a reflex to turn the lamps on and off with ignition when regularly operating such a vehicle, like our older car.)
In a car with dusk-activated headlamps, one has to worry about both cases. The low-light sensor doesn’t trigger in most rain or snow (and the lamps don’t turn on with the windshield wipers, which might also be sensible), so the headlamps are effectively manual in this case. (This also holds more generally; conditions outside might well be dim enough so that one would prefer headlamps, but not dim enough to activate the automatic lamps.) Because the times when manual intervention is necessary crop up arbitrarily, what should be a reflex instead becomes an attention-demanding, multi-step process.
Worse still, it isn’t possible to turn off the Vibe’s headlamps if the car believes that they should be on. Instead of providing an intuitive, manual solution that inspires habit and reflex or an automatic solution that requires zero effort at all in the overwhelmingly common case, the Vibe headlamp design assumes that it knows better than you do when the headlamps should be on and offers no provision for overriding its advice. At least it isn’t also controlling my pod bay doors. By being too clever, this design is actually more user-hostile than two substantially “dumber” alternatives.
Of course, the don’t be too clever principle isn’t merely confined to automatic headlamps. Countless designs fail spectacularly because the designer has incorrectly assumed that there is only one reasonable way to expect the product to behave or to interact with it. (Note that correctly assuming that there is only one reasonable way to interact with something is one of the hallmarks of excellent design — and perhaps the hardest to get right!) At least in the case of the Vibe, I can put a small card over the light sensor (which is on the dash) and get my always-on headlamps. There’s no such luck when some web application capriciously disables my “Back” button.
POSTSCRIPT: Apparently, the 2008 Vibe features always-on headlamps. I guess you can’t please everyone, since the internets are full of people complaining about this feature and asking how to disable it.