Charleston County is pushing for more control of construction of the extension of Interstate 526 across Johns and James islands, a move that likely is slowing down the project.

County Council voted by a narrow margin in December to move forward with building the controversial road, which would complete a highway loop around Charleston. But after more than seven months, the county still hasn’t taken any concrete steps forward, including the first required step of amending and updating the project’s three-part contract, known as an intergovernmental agreement.

The project was planned as a collaborative effort between the county, which would sponsor it; the South Carolina Department of Transportation, which would manage and build the road; and the S.C. Transportation Infrastructure Bank, which would pay for it.

The original agreement between those three groups must be updated, including the cost, which has risen from $420 million to $558 million.

Council Vice Chairman Elliott Summey said the county wants to play a larger role in building the road, even though the management of such large road projects usually is left to the South Carolina DOT.

And it wants more input on right-of-way acquisition and mitigation for the impact the road would have on nearby property owners. “Local government is where the rubber meets the road,” he said.

While Summey is pushing for more control of building the road, project opponents, including the Coastal Conservation League, said that would be another in a string of missteps. “What we’re looking at here is a Chinese fire drill at the county level,” said Dana Beach, the league’s director. “If we want to see a higher level of dysfunction,” he said, “we should turn it over to the county. It will only get worse.”

Summey said he and some county administrators plan to make a presentation on the project to the Infrastructure Bank’s board Wednesday. It’s part of the process to complete the amended agreement, he said.

Debra Rountree, the bank’s director of operations, and Donald Leonard, chairman of its board, said the issue so far is not on the agenda, which hasn’t yet been released.

The bank’s board must approve the amended agreement, Rountree said. And she has heard from DOT commissioners that they want to weigh in on the agreement, even though they may not be required to do so.

DOT spokesman Peter Poore said the group “is still in the process of modifying the existing IGA for the Mark Clark extension. That will require some time.”

Charleston County Council, however, doesn’t have to approve the amended plan. It gave that responsibility to county administrators in December as part of the 5-4 vote to move forward with the project.

Councilman Dickie Schweers, a strong opponent of the project, said the majority of the board that voted in favor of it did that “to cut us off from being able to challenge it in the future.”

He said I-526 is one of the largest construction projects not only in the county but in the entire state, and he doesn’t think the county has the resources and skills to build it. He thinks the majority of the board is pushing for control because it “fears the politics of the DOT.”

Some DOT commissioners previously have raised concerns about spending such a large amount of money on a project that is not a regional or state priority.

Schweers also said he thinks taking control of the project will put county taxpayers at risk.

“I think this project is littered with mistakes,” Schweers said, but he can’t predict whether any of them are severe enough to create a legal challenge that might stop it. “It certainly was not a clean process that passed the smell test,” he said.

Citizens’ groups continue to disagree about the project.

Braden Davis, a spokesman for Charlestonians for I-526 said his group supports the county taking over building the road. But members would get behind whoever can build it the most quickly. “Let’s get it done,” he said.

Rich Thomas, a member of the opposition group Nix 526, said the county simply doesn’t have the ability to complete such a massive project. “It’s just laughable that a $600 million contract is something the county needs to take on.”

Reach Diane Knich at 937-5491 or on Twitter @dianeknich.