In Choosing the public/private mix in delivery, as part of CEDA’s information paper on Infrastructure and economic development released in 1999, the authors assessed what an optimal infrastructure delivery mix should look like.
They concluded that under certain conditions, such as severe fiscal constraints on government, private sector ownership would deliver better results. They warned, however, that these conditions are often not present, leaving the optimal private/public mix to be judged on a case-by-case basis in many instances e.g. urban roads.
Read chapter four: Choosing the public/private mix in delivery.