MnDOT tried to get contractors to finance the reconstruction of the Crosstown Connector in Minneapolis and Richfield, a major bottleneck where the Crosstown Highway (Mn 62) and I-35W share real estate. This was clearly a move towards innovative financing, not just letting contractors build the project, but letting them pay for it, with no certainty about repayment. Clearly, Minnesota's "uninnovative" contractors were having no part of it. See the Strib for details: Crosstown project fails to draw a bid
Generally for financing, there needs to be some guarantee of repayment, with some interest earned, proportionate to risk.