It was only last June that Illinois Gov. Pat Quinn and Indiana Gov. Mike Pence hosted a conference to reboot plans for a 47-mile-expressway linking their two states, a project originally proposed by Quinn and then-Indiana Gov. Mitch Daniels in 2010.

Since June, plans have proceeded at brisk pace, like a car riding a shoulder, no doubt because the east-west “Illiana” Expressway not only would create tens of thousands of jobs, but cost taxpayers in both states nothing. Or so taxpayers have been promised. As planned, private investors would fund construction of the $1.5-billion expressway in exchange for all or a portion of tolls it would generate.

In October, the Chicago Metropolitan Agency for Planning approved the project, despite concluding the jobs and tolls it would generate are overstated and that taxpayers likely would be left holding the bag.Though the Northwest Indiana Regional Planning Commission won't vote on the project until Dec. 12, the State of Indiana kicked off a search for investors earlier this month. IDOT also is soliciting investors, calling for substantial completion of the project by 2018.

Illiana isn't without critics. Environmentalists have filed suit in federal court, contending it would endanger wildlife, critical habitats and farm land. Even so, the Illinois Department of Transportation intends to resolve final issues with state and federal environmental agencies by the end of this month.

Despite heavy congestion on I-80, an east-west corridor south of Chicago, the Chicago Tribune recently questioned whether truckers would willingly divert to a parallel corridor much further south of the city.

It's a question worth asking. In October, Crain's Chicago Business reported that the State of Texas likewise lined up a private consortium to construct a $1.2-billion, 41-mile tollway near Austin, only to discover that drivers preferred an existing free road. In fact, traffic on the tollway has been so low that that Moody's Investors Service lowered its rating on the tollway company from B1 to Caa3: junk.

Assuming planners have done their homework, Illiana could serve as a model for P3s throughout the region. If poorly executed, it could put the brakes on P3s for years to come.