Not long ago, the 23 service plazas along Connecticut's highways were shabby and out-of-date. Kevin Nursick, a state Department of Transportation spokesman, said they were “dilapidated hellholes. They were dungeons. They were disgusting.”

Then, in 2009, then-Gov. M. Jodi Rell announced plans for a public-private partnership that would pump $150 million in funding into renovations that would make the plazas fit for public respite. But the project's aftermath has left behind a slew of subcontractors complaining—and at least a few suing—over $5 million in unpaid bills. The DOT has had to intervene in the tangled contractual dispute.

The private sector entity formed to rehab the plazas is Project Service LLC, a joint venture consisting of asset-investment giant Carlyle Group, Doctor's Associates (the parent company of Subway Restaurants) and another corporation, Subcon. In return for making service plaza upgrades on Route 15 (the Merritt Parkway) and Interstates 95 and 395, Project Service would get to run the plazas for 35 years and keep the profits, save for an annual $2 million payment to the state.