How many little kids have to die before we'll install seat belts in buses?

Yesterday in Arlington a school bus crashed head-on into a garbage truck, tragically kiling one grade schooler. It's ironic because just last weekend my dad and I were talking about how reprehensible it is that we, as a society, have an unlimited amount of funds to bomb the living shit out of anyone, anywhere, anytime, yet we deem it "too expensive" to mandate and install seat belts on school buses. I remarked to him that, like seemingly every major regulatory change, it will take a major accident before this issue is properly addressed. Well, here it is. :-(