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.

Easy, there's a known correlation between cost of air travel and fly vs drive tradeoff decision consumers take. Conveniently, price of travel tends to vary, independent of all other variables, with the price of oil to produce jet fuel, and at a law different from the one of variation of cost of road travel for the same reason, thus providing an easy way to measure how people make that decision (highway travel miles variability is measured by gasoline sales variability and number of air tickets sold daily is also known). So they know how many people will drive instead of flying if price of a ticket increases by X% without anything else changing.

By extension anytime an airline raises prices it kills children; reducing prices saves children.

QED

Yeah, but the FAA doesn't have authority to set prices, this is a pretty cool example of doing what they can with the variables the do control.

In the software world everyone is really obsessed with quality as an isolated thing, they want beautiful code and fast performance, and workarounds for external variables you don't control are disliked, programmers have a "Let it fail" kind of attitude.

Always interesting to look at the life safety stuff and what they do when failure is not an option, and it doesn't matter who's fault it is, you make it work if you can.