The Atlanta region's transportation wish list just bulked up.

State transportation officials have weighed in, adding new projects such as a MARTA line to Roswell, several interchanges on I-285, and a half-billion dollars worth of Xpress buses to the projects that voters might consider in a referendum next year that would add a penny sales tax.

The list shed projects deemed too local or vague to pass muster with the law and excite the voters.

But now it will all have to be cut down to size.

A group of 21 local elected officials must take those $22.9 billion worth of projects and jettison about $15 billion of them, because the penny tax would raise only about $8 billion over its 10 years.

The projects they choose will be the key to swaying voters.

Todd Long, the state's transportation planning director who did the adding and deleting over the past two months, said the MARTA extension to Roswell was one of the projects that would appeal to a lot of residents. Some of them interviewed Wednesday agreed.

“Yes!” cheered Miriam Pagan and her daughter, Mia Maldonado. Maldonado, 22, said she’d go back to school in downtown Atlanta if the line got built, and Pagan, 40, said she could stop rearranging her schedule to drive her daughter around. Mike Mader, who drives to work in Atlanta, said he'd switch to the train from time to time if it came as far as Roswell.

Other newly added projects drew support, too. In Cobb County, Carey Averbach, who owns a stone refinishing business, grew increasingly agitated as he said something has to be done about the I-285 interchange with South Cobb Drive, a project Long added to the list. If it takes paying a penny, "I don't care," he said. "It's just an accident waiting to happen."

The tax also has drawn opponents. Not just tea party adherents, but residents who can't see raising their taxes.

Even the Ga. 400 MARTA extension doesn't sway Aubrey Brooks of Roswell, a 21-year-old manager of a men's hat store at Cumberland Mall. "Extending the rail line wouldn't matter," not enough to raise taxes, he said.

Counties and cities in metro Atlanta submitted their wish lists in March. Long has added more than 150 new proposals, and he has deleted more than 140 others. Other projects, such as a $2 billion rail line to Sigman Road, had no official sponsor and died in the process.

Long has given the new list to the 21 mayors and county commissioners who now will cut it down to an affordable size.

“We ended up giving them a list that is nearly three times the amount of available money that’s going to be raised in the region,” said Long. “The cuts they’re going to have to make to get down to a constrained list I do not envy.”

Nothing in the law prevents Long from adding more projects later this summer if he sees the need, but he doesn’t see one now, he said. For the moment, this is it: $14 billion worth of transit projects, $8.6 billion worth of road projects, $205 million in sidewalk and bicycle projects, and $28 million for aviation.

Long emphasized that the $14 billion price tag for all the transit was just a reflection of the high cost of new transit capital projects, not his opinion on how much the region should spend on such projects.

Long’s additions include a new Amtrak station, optional toll lanes along I-75 and I-575 in Cobb and Cherokee counties, 62 specific Atlanta bridge and road rehabilitation projects, and road widenings such as Roosevelt Highway and Ga. 138.

To help reach voters, the Atlanta Regional Commission plans to invite 1 million households to participate in telephone town halls -- starting this month -- on the referendum. Information about the list and the roundtable is available at www.atlantaregionalroundtable.com and at ajc.com.

Roundtable members will need their input, private polling data they are expecting about individual projects, and a stiff spine to make the right decisions on what to cut and what to keep, local officials said.

“I think it’ll be one of the most difficult decisions that these roundtable members will face in their elected offices,” said Johns Creek Mayor Mike Bodker, who is working with a south Fulton mayor to exercise the county’s vote.

"I would second that," said Norcross Mayor Bucky Johnson, who chairs the roundtable. "In my case, it’s the biggest decision. It’s not a halftime show here. It’s something that will affect generations to come."

Bodker is ambivalent about the idea of Ga. 400 transit. While he favors transit, he said it has to be the right project, a sustainable one, so he’d like to see it studied first. MARTA staff did not put the project on the agency’s list because of the difficulty and expense of crossing the Chattahoochee River to get to the next jobs center, staff members told their board.

But other officials in north Fulton favored putting the $839 million line on the list, Long said. It might raise hopes for something that doesn’t get chosen, but “I think that’s a risk you have on all the transit projects,” he said, adding that the roundtable would get data soon on the transit projects to let them know which were more likely to get built in a reasonable amount of time. However, Long added, “There’s no doubt that that project would have a lot of appeal to the public.”

Long didn’t need polling to tell him that unspecified pots of money were a bad idea if you’re trying to paint a picture of exactly how specific projects will improve voters’ lives, he said. He removed some of those from the city of Atlanta and DeKalb County, replacing them with actual projects, which he chose working with the local governments, he said.

That didn’t sit well with Atlanta City Councilman Lamar Willis, who represents the city at the Atlanta Regional Commission. “It does create some concern,” he said, pointing out that city residents pay the MARTA tax, money that in other counties might instead be going to road maintenance. “Whatever it’s replaced with, it has to be something that we can sell to our constituents so they can be supportive of this referendum.”

Long deleted some projects because they were not in the region, and the tax money must be spent in the region, he said. He deleted others because they were too local, such as neighborhood road projects in Gwinnett County. Some trail projects, such as a proposal to extend the Silver Comet Trail from Cobb County to downtown Atlanta, he determined were primarily recreational, not for transportation.

Just because a project made the list, that doesn’t mean it would be fully funded. For example, the project to add optional toll lanes along I-75 and I-575 in Cobb and Cherokee counties is now on the list for $50 million -- a small fraction of the $1 billion it would take to build. The rest could come from toll money and state gas taxes.