I am buckling in seatbelts from the front.

We can't risk alienating them by testing seatbelts relative to car seats.

It doesn't turn out to be the case when you look at seatbelts versus car seats.

And so, you can see that the lap only seatbelts start to look worse once you do that.

But indeed, in recent crashes the lap and shoulder seatbelts, actually, are doing even better than the car seats.

So the yellow bar represents car seats, the orange bar lap and shoulder, and the red bar lap only seatbelts.

And the free cure is adult seatbelts, and the expensive cure the 300 million dollar a year cure is child car seats.

(Audience I just wanted to ask you, when we wear seatbelts we don't necessarily wear them just to prevent loss of life, it's also to prevent lots of serious injury.

Steven Levitt shares data that shows car seats are no more effective than seatbelts in protecting kids from dying in cars. However, during the question and answer session, he makes one crucial caveat.

That's an awful large lot of very nice people. On the other hand, when a bus blows up and 30 people are killed, more people than that were killed by not using their seatbelts in the same country.

And the line of argument, if you ask parents, is, But car seats are so expensive and complicated, and they have this big tangle of latches, how could they possibly not work better than seatbelts because they are so expensive and complicated?

Is there any data to show that child seats are actually less effective, or just as effective as seatbelts for serious injury? Because that would prove your case.) Steven Levitt Yeah, that's a great question. In my data, and in another data set I've looked at for New Jersey crashes, I find very small differences in injury.

And what I'd like to talk to you about today is some of the evidence why I believe this to be true that for children two years old and up, there really is no real benefit proven benefit of car seats, in spite of the incredible energy that has been devoted toward expanding the laws and making it socially unacceptable to put your children into seatbelts. And then talk about why what is it that makes that true?