It is in the best interest of the child to fix the public school. In the case a failing public school a voucher program might help some students but it will abandon many others. Those abandoned students are the ones we will most likely be supporting later.
Of course the roads were used to bring these necessary things. The public schools were also used to educate the people who made and transported these items. That is my point. As a society we are benefit or suffer according to how the next generation is educated.