It's a ridiculous notion -- the government has the ability to raise capital far more cheaply than private capital markets, and revenue from toll-roads is one of the most reliable revenue streams that exist. It's not zero-risk, but pretty close.
It's just a scheme to move debt to somebody else's books, and make more money for various parties. It also provides fertile ground to re-direct anger from government operational incompetence or underinvestment, like plowing in such a way that you create miles of gridlock instead of doing things like pre-treating the road surface to avoid plowing during peak travel times.
I don't think privatized prisons charging $14/minute for phone calls is a good thing either, even if the "market" (prisoners needing to call their lawyers, and having no other options, etc.) allows it.
https://www.expresslanes.com/project-background
> In 2007, VDOT finalized a long-term partnership agreement with Capital Beltway Express, LLC – a consortium led by Transurban that would design, build, operate, finance and maintain the $2 billion HOT lanes project. Transurban and its partners provided a substantial upfront equity commitment to help fund construction and financed the rest of the project through private activity bonds and a TIFIA loan. The partnership enabled Virginia to leverage private capital to translate every one state tax dollar into four dollars of transportation improvements.
>Construction, managed by Fluor-Lane, began in 2008 and the new lanes opened for business in 2012.
>In 2014, Transurban invested an additional $280 million of equity to put the project on solid financial footing following impacts of the global financial crisis. The private sector has assumed the long-term financial risk for the project, including full responsibility to pay back all project debt.