From Stephen J. Dubner and Steven D. Levitt, the authors of "Freakonomics: A Rogue Economist Explores the Hidden Side of Everything" with The Seat-Belt Solution : "...one question about car seats is rarely even asked: How well do they actually work?
They certainly have the hallmarks of an effective piece of safety equipment: big and bulky, federally regulated, hard to install and expensive. (You can easily spend $200 on a car seat.) And NHTSA data seem to show that car seats are indeed a remarkable lifesaver. Although motor-vehicle crashes are still the top killer among children from 2 to 14, fatality rates have fallen steadily in recent decades -- a drop that coincides with the rise of car-seat use. Perhaps the single most compelling statistic about car seats in the NHTSA manual was this one: 'They are 54 percent effective in reducing deaths for children ages 1 to 4 in passenger cars.'
But 54 percent effective compared with what? The answer, it turns out, is this: Compared with a child's riding completely unrestrained. There is another mode of restraint, meanwhile, that doesn't cost $200 or require a four-day course to master: seat belts.
...For children younger than roughly 24 months, seat belts plainly won't do... Even a quick look at the FARS data reveals a striking result: among children 2 and older, the death rate is no lower for those traveling in any kind of car seat than for those wearing seat belts.
So if car seats and booster seats aren't the safety miracle that parents have been taught to believe, what should they do? The most important thing, certainly, is to make sure that children always ride with some kind of restraint...
It may be that the ultimate benefit of car seats and booster seats is that they force children to sit still in the back seat. If so, perhaps there is a different contraption that could help accomplish the same goal for roughly the same price: a back-seat DVD player. "