Congressional Democrats may introduce legislation that could punish states for leasing US toll roads, a move that could throw cold water on public private partnerships and private equity infrastructure investment.

Last week the US House of Representatives Highways and Transit Subcommittee published a report outlining concerns over public private partnerships. The report is in favour of states forging relationships with financial institutions such as private equity firms, but cautions against charging "excessive tolls" and providing "excessive profits" to such companies.