State and local officials struck an agreement in 2014 to transfer the managed lanes along Interstate 10 from the Harris County Toll Road Authority to the Texas Department of Transportation.

Three years later, the deal remains held up by one nagging detail: how to make it legal.

"We just haven't done it yet," Harris County Judge Ed Emmett said, noting he is confident it will happen. "The lawyers are still trying to sort it out."

The proposed transfer is at the heart of an agreement to restructure an earlier funding plan to speed up construction on the widening of U.S. 290 from Loop 610 to Waller County.

That original deal - hailed as a cooperative breakthrough in 2012 - called for the toll road authority to contribute $400 million to the $1.8 billion widening project.

The two agencies agreed to restructure the deal in 2014 after the county and state differed on preferences for designing high occupancy toll, or HOT, lanes in the center of U.S. 290. State officials since have changed the plans to build a single, reversible lane rather than the three originally envisioned.

The agreed-upon restructuring would see the county reduce its contribution to $200 million but give the Katy Managed Lanes along I-10 to the state so it could recoup toll revenues for the 290 project.

Or at least it will reduce the contribution, once officials can ink a deal. Emmett said when the agreement was discussed, lawyers said it would be complicated.

"We told them to figure it out," he said.

Turns out, it was more complicated than expected.

HCTRA was established by voters with the authority to borrow money to improve transportation in Harris County. Its debt is repaid by tolls, but for financing purposes, projects are not considered separately.

"The whole system is financed," Emmett said.

This type of financing is why tolls are not removed from projects, because the agency continually operates with debt long after it raised enough money to pay off its original bonds.

Repayment of HCTRA's debt, meanwhile, is based on its revenues, including what it expects to receive from operating the I-10 lanes.

The lawyers, Emmett said, are trying to write an agreement that allows HCTRA to cede control of the lanes to TxDOT without upsetting its promise to repay its debts and without TxDOT becoming responsible for paying any money back.

"TxDOT can't take on our debt," Emmett said.

Reversible lanes

The agreement sitting dormant does not affect operation of the managed lanes, nor will regular drivers notice when the lanes are in state hands. All toll payments on the I-10 lanes are electronic, though billing and collections would fall to state officials.

When the original deal was struck, officials said it also divided local toll facilities more cleanly. HCTRA, which builds and manages its own facilities, would continue to maintain those while TxDOT and Metro maintain the lanes along major freeways, which cater to carpools and toll-paying solo drivers. TxDOT also owns and operates the Grand Parkway.

When the widening of U.S. 290 is completed - in late 2018, based on current estimates - it will have five general-use lanes in each direction and one HOT lane from Loop 610 to Texas 6 and four lanes in each direction from Texas 6 to Waller, with a HOV lane in the center.

Meanwhile, TxDOT and Metro are working on a plan that would make one lane of the freeway an off-peak reversible carpool lane, which would speed transit and reverse commutes along the freeway. Under the plan, the interior outbound lane would be open only to carpools and buses in the morning while the HOT lane operates inbound. When the HOT lane is flowing outbound in the evening, the interior eastbound lane would be HOV-only.

'Need to get that done'

That agreement, like the one with HCTRA, remains a work in progress, as the widening project stretches two years later than predicted. Heavy rains in 2015 and 2016, lengthy waits in relocating utilities and contractor replacement on a major segment led to the delays.

As workers hustle to complete U.S. 290, however, officials said none of those outstanding agreements between the county and state are having an effect on paying for or completing construction.

"Negotiations that are also ongoing between TxDOT and HCTRA have nothing to do with the progress of the many projects in the area," TxDOT spokeswoman Veronica Beyer said.

County toll road officials also said the lack of resolution is not impeding them.

"HCTRA has been working on a number of other high-priority projects with major impacts to our agency and the region, such as the Sam Houston Tollway Ship Channel Bridge project and deploying a new back office system," HCTRA spokeswoman Roxana Sibrian said.

Various priorities on both sides, Emmett said, have kept the restructured agreement on the back burner, though he said it needs to get done eventually.

"The last three times I have run into (Texas Transportation Commission chairman) Tryon Lewis, we both look at each other and say 'We need to get that done,'" Emmett said. "We just haven't, and somehow we've got to... We still technically owe TxDOT $200 million."