The Progressive Legislative Action Network (PLAN) has a short piece on their site addressing the question of who should own toll roads. Given NC's recent attraction to the idea, it's worth a read:
Allowing some private investment in building infrastructure is not the problem – that's common in countries around the world. The corrupt aspect of many of these new state projects are the extreme long-term leases that undermine democratic control of our transportation infrastructure for multiple generations. And in both Indiana and Texas, not only will private companies control the roads they lease, they will have "noncompete" contracts that allow them to block any new roads in the same area that future governments might decide to build.