The cost of childcare seems way underestimated, at least for young children.

It shows $13,641 for my metro (Chicago), but day care costs are easily twice that. Obviously once kids are school-age this is much lower (if going to public school), so maybe that's how you get at this figure.

On the other hand the transportation costs are way overestimated for non-car families (we spend less than $2k/year on local transit for 2 adults and 1 child, obviously this doesn't include airfare for vacations or whatnot). Maybe these are both an artifact of too broad a catchment area (childcare is probably cheaper in the 'burbs, but so likely are average transportation costs).