Before a $6.1 billion transportation project list is set in stone for the region, metro Atlanta residents have their last chance to comment at public forums this week.

The list seems likely to change, and there’s not much time left.

A group of 21 mayors and county commissioners called a "roundtable" is to finalize the list by Oct. 15, but probably earlier than that, at meetings Oct. 6 and Oct. 13. Voters will consider the list next year in a referendum, along with a 1 percent sales tax to fund it.

The officials drew up a first draft of the project list Aug. 15. But it will probably change, because they did not include extra administrative costs, and now must find a way to pay for them.

The chairman of the group drawing up the project list, Norcross Mayor Bucky Johnson, said he thought it would be “a distraction” to include them while his committee was in the grueling battle to create the first draft.

Early estimates for the administrative costs ranged from $50 million to $100 million, Johnson has said, though he, other members and staff emphasized they didn’t have good numbers yet. At the group’s last meeting, some discussed the possibility the costs would take up 4 percent of the list -- $246 million -- but then members and staff said such a high number was unlikely.

Gwinnett County Chairwoman Charlotte Nash heads the committee that deals with the administrative costs, and she is expected to present better figures at a meeting Wednesday.

The regional list can spend only $6.1 billion, and that’s how much it adds up to now. To make way for the extra administrative costs, that means either projects must be reduced in size, or some projects must be taken out, or the region has to find someone else willing to foot the bill for the extra administration.

Some regional officials suggested putting in no money at all for the costs and essentially insisting transportation agencies foot the bill. But that wouldn’t work, said Todd Long, state transportation planning director. In that case, he said, the state Department of Transportation would just take the money out of the project funds, reducing the size of each project.

There is an additional stream of money if the tax is approved: Fifteen percent of the tax, or $1 billion, would go back to the counties and cities where the tax was raised, based on population and the number of lane miles. But the region would apparently need each of those counties' and cities' permission to use that money.

In addition to the problems with administrative costs, issues have arisen with the level of money allotted in the list for Xpress commuter bus service, a concern for suburban counties. Georgia Regional Transportation Authority Director Jannine Miller wrote to roundtable members telling them that with the current allocation in the draft, Xpress bus service would likely undergo drastic cuts.

The list is being chosen by a “roundtable” of 21 mayors and county commissioners from across the 10-county region. They are holding 12 public forums across the 10 counties.

The final meetings are this week, Monday through Thursday in Gwinnett, Rockdale, Fulton, DeKalb and Clayton counties.

At the meetings, staff members are there to answer questions about the projects and the process, and local roundtable members usually attend. Roundtable members say that in choosing the final project list, they will take the public comment into account.

The roundtable will still accept individual comments after that.

Remaining meetings

  • 5-7 p.m. Monday

Gwinnett Justice and Administration Center

75 Langley Drive, Lawrenceville

  • 6-8 p.m. Tuesday

Rockdale County

J.P. Carr Community Center

981 Taylor St., Conyers

  • 6-8 p.m. Wednesday

South Fulton Service Center

5600 Stonewall Tell Road, College Park

  • 6-8 p.m. Wednesday

DeKalb County

Manuel Maloof Auditorium

1300 Commerce Drive, Decatur

  • 6-8 p.m. Thursday

Clayton County Administration, boardroom

112 Smith St., Jonesboro

More information is available at atlantaregionalroundtable.com.