The gist of it seems to be this:

>>> Requiring the use of CRS for children under two would significantly increase the price of family air travel for a small targeted population • Price affects consumer decisions • Would cause some families to divert to the highways, a much higher risk mode of transportation. • For every child under two saved by a regulation (1 every ten years), a minimum of 60 lives would be lost on the highways.

I didn't read the whole thing. I'm not sure how they think they know this is what would happen.