Cobb County taxpayers are still in the dark about how much the bright lights of Major League Baseball will cost them.

Not even members of the Cobb-Marietta Coliseum Authority board, which will ultimately have to approve the financing deal, know the price, or where the revenue will come from to repay the bonds.

Authority board member Steven Tumlin Jr., Marietta’s mayor, said “we’re all on pins and needles.”

The Atlanta Braves announced Monday their intention to leave Turner Field when their lease expires in 2016 for a new ballpark and mixed-use development in Cobb County, near interstates 75 and 285. They also said the Cobb-Marietta Coliseum Authority would issue the public debt.

Cobb County Commission Chairman Tim Lee said for a second day in a row that he would not comment on the public’s commitment to the project because details are still being finalized with the Braves.

Atlanta Mayor Kasim Reed says Cobb has agreed to $450 million, or two-thirds of the project’s overall cost, and that he learned the number from someone in the negotiations. Lee and the Braves have said that figure is inaccurate, while still refusing to comment on the amount. The commission chairman didn’t budge from that position Tuesday.

“We’ve come to a handshake agreement of what we will do,” Lee said. “Those discussions are being put on paper and fine-tuned. It’s important that when I make the announcement that I have it nailed down tight. That’s smart business.

“I need to know I can stand behind it when we put something out.”

Critics say Lee’s secrecy runs counter to promises made in his re-election campaign, during which he said important decisions would be based on “consensus and partnership, with deliberate outreach to the citizens of Cobb County.”

The Coliseum Authority, which has issued debt to fund the Cobb Galleria Centre, the Cobb Energy Performing Arts Centre, and Galleria Specialty Shops, ran a $1.5 million deficit in fiscal year 2012, the last year for which figures are available. That deficit knocked down the authority’s savings account to $18 million, according to its financial statement from that year.

It is a little-known seven-member board that derives most of its revenue from taxes on hotel rooms and alcoholic beverages sold by the drink. It was created by the state Legislature in 1980 build and maintain facilities that “promote cultural growth, education and welfare.”

Tumlin speculated Tuesday that the authority would have to issue revenue bonds, which are repaid by funds generated from the development. When asked if there is sufficient revenue for the authority to take on a large amount of debt, Tumlin answered: “Not right now.

“That’s what the lawyers are probably putting together, something to show us (how) we can do it,” Tumlin said.

Some residents are growing impatient.

Bill Byrne, former chairman of the Cobb Commission who served on the authority for 10 years, said the public has a right to know the amount being committed in its name.

“There’s an awful lot of suspicion about what’s going on here,” Byrne said. “If anyone believes Tim Lee was just contacted about this a few months ago, they’re smoking something funny. Why he is keeping the amount secret is beyond me.”

Lee said Monday that discussions with Braves officials started in July, over dinner at the exclusive Marietta Country Club.

Lance Lamberton, president of the Cobb Taxpayers Association, said spending hundreds of millions of public dollars on the stadium “sounds to me like a giveaway to the people who own land” near the stadium site.

Lamberton also worried that the new stadium would become a “Trojan horse to get MARTA into Cobb County.”

“Traffic is already so bad in that area right now,” he said. “They build this, traffic becomes intolerable, and that changes public opinion.”

Both Lamberton and Byrne suspect that the county will attempt to introduce light rail transit to mitigate traffic congestion around the ballpark.

That was a sentiment shared by Reed Tuesday at a news conference.

Atlanta’s mayor said the Braves got a “terrific deal.”

“It’s one of the best deals in America,” Reed said, adding “if Cobb goes forward with this, they’re going to have to have rail. Which would be the first introduction of light rail.”

Cobb Commissioner Helen Goreham said she has seen the financing numbers and said it is “mostly legalese being worked out at this point.” She declined to comment on the county’s financial commitment.

When asked why, she referred questions back to Lee.

“That’s a good question for the chairman at this point,” Goreham said. Later, she added: “This is not an attempt to be secretive. It’s an attempt to go through a process, do it correctly, get the correct information out there and be as forthright as we can be.”