Metro Atlanta voters know little to nothing about a high-stakes transportation sales tax they’ll consider next year, and they don’t quite trust it.

But they’re so concerned about the region’s future that a slim majority of 51 percent say they’ll vote for it anyway.

A new poll commissioned by The Atlanta Journal-Constitution and Channel 2 Action News asked voters for their views on a proposed sales tax to pay for transportation projects in the 10-county region. The plan now tops the regional agenda both for business leaders who argue metro Atlanta’s future is at stake and for anti-tax hawks who fear the economic consequences of a tax hike.

If approved by voters in 2012, the referendum would levy a 1 percent sales tax in the 10-county metro Atlanta area. It is expected to raise $6.1 billion over 10 years for regional transportation, and a list of projects is being finalized now.

Metro business leaders are so concerned about congestion blocking economic growth that they plan to put millions of dollars into a public awareness campaign to pass the tax. Opponents have come out swinging.

For those who want the tax to pass, the road to the vote is a long one.

If the vote were held today, the smallest of majorities say it would support the measure, said Brad Coker, managing director of Mason-Dixon Polling & Research Inc., which conducted the poll. Thirty-six percent said no, and 13 percent were undecided, according to the poll.

The respondents’ feelings will come as no surprise to anyone who has braved metro highways. Two-thirds said congestion was undermining the region’s quality of life. Moreover, 91 percent said the region’s transportation problems were important to address for the sake of its quality of life and economic future.

That doesn’t mean just roads. The first draft of a project list spends just over half the money on mass transit, and that mix drew support from 57 percent of poll respondents. Paradoxically, majorities said they would like more of the money to go to both roads and mass transit.

The strongest support comes from Clayton, DeKalb and Fulton counties, the referendum’s crucial base. Support waned in the inner suburbs of Cobb and Gwinnett counties, with 48 percent in favor and 10 percent undecided. But that’s a more accommodating picture than appeared decades ago in overwhelming anti-transit votes, and it shows the changes that have swept metro Atlanta in the past two decades, Coker said.

Howard Shatzman of east Cobb supports the plan in part for personal reasons: the inconvenience of driving in congestion, and when his son was at Georgia Tech he had to call for a ride to visit home because there was no train in Cobb. But for Shatzman, it’s also a matter of civic duty.

“I’m a conservative. I am not a flaming liberal. But I believe that we have to do certain things,” he said. “Moving your people efficiently is crucial for a great city.”

Shaun Hagler agreed. “I think it’s a necessary — I don’t even want to say ‘evil’; it’s necessary,” said Hagler, a 41-year-old from Alpharetta who will start attending Emory University extension classes next month to become a paralegal. “I mean the traffic congestion is pretty bad,” and there aren’t enough good roads or buses, he said.

“It’s just going to become more populated,” he said. “They might as well get ready.”

A fragile lead

There are two ways to look at the 51 percent.

Conventional wisdom says it’s a danger sign, Coker said: A ballot measure’s strongest position is when the idea is first proposed. From there on out it’s the opponents’ game because they can poke holes in support by raising questions.

“The rule of thumb with referendum polling is, if there’s any doubt in a voter’s mind at the end of the day, they will vote no and maintain the status quo,” Coker said. “I’ve seen a lot of referendums that start out early with support in the mid-50s, in the end end up losing 48-52 or 47-53.”

But the referendum’s proponents have an argument that Coker said he might buy. They say this type of referendum is different because there will be a map of transportation projects that people vote on, not an abstract idea. At least two-thirds of people don’t know much about the referendum or what it will build, according to the poll. That’s a gap supporters say they can remedy.

“There is not a [final] project list yet,” said Paul Bennecke, a strategist of the privately funded political campaign that may spend more than $6 million selling the referendum. “We will get that here in the next couple of weeks. And there is going to be a full-fledged campaign that will spend a lot of money educating voters on what the impact is on them improving quality of life and addressing traffic congestion.”

Bennecke knows it will have to do more than that to succeed.

The poll found weak spots not just in the voters’ knowledge, but somewhere more dangerous: their trust.

A solid majority did not believe the tax will end when the law says it will, or that it will be spent on the projects on the approved list. According to the law that set up the referendum, the tax must end after 10 years. Most of it, $6.1 billion, must be spent on the regional list of projects, and $1 billion will be spent by counties and cities on unspecified local transportation projects.

Most striking to Coker, 41 percent felt that mistrust strongly. “If I were in the opposition,” Coker said, “I’d start there.”

The mistrust surfaces with both supporters and opponents. For retired Navy Petty Officer John Richardson, it’s one reason to defeat the tax. “It’s just another tax that’ll never be repealed,” he said.

Richardson took his lesson from the Ga. 400 toll, which was supposed to end this summer but was extended by state officials who said transportation funding was too scarce. “They never have repealed a tax on toll roads or kept any temporary tax from going permanent,” Richardson said.

The Ga. 400 toll decision “is very fresh in people’s minds,” Coker said. “That’s why right now that’s the most vulnerable part of the proponents’ argument.”

Lynn Martinez, 45, is leaning yes but said she was undecided. Trust is an issue — she wants to believe the politicians — but she said she can get over it. The important thing for her is that the project list be a good one.

“I am for it if it’s a good proposal,” she said. “If it makes sense.”

But that’s another issue: What is the right project list? For Martinez, good means more mass transit. But for others, it’s roads.

The controversy around mass transit is the hottest one right now for members of the “regional roundtable,” a group of 21 mayors and county commissioners that is forming the project list.

The draft list of projects gives more than half the $6.1 billion to mass transit projects, including major rail expansions such as one to Cobb’s Cumberland area.

Seydell Hood, born and raised in Atlanta, has a car, but she wants her grandchildren and other people who can’t afford cars to be able to get around. “I have a lot of friends and relatives that use public transportation,” Hood said. With the tax, “I don’t particularly see anything in it for me,” she said, but for them, “it’s access to jobs.”

In a city of Atlanta public forum on the tax, a barrage of speakers defended mass transit and asked for more.

But in some forums in outlying counties, the message was the reverse.

It’s hard to know if the loudest message comes from the largest number of people. But while only 20 percent of poll respondents said they regularly used mass transit, 82 percent said they think it is important to do more to encourage its use.

The vast majority of people think the tax would be more likely to pass if a regional transportation authority, not MARTA, manages the mass transit. The law puts the Georgia Regional Transportation Authority over the transit projects but MARTA is likely to continue to run the Fulton and DeKalb systems.

A notable minority, 42 percent, believe that new mass transit would bring crime with it.

First shots fired

Forty-two percent of poll respondents don’t support any tax increases. Tea party representatives have led the organized opposition to the tax so far, but they don’t make up a majority of the region. Five percent of voters surveyed said they consider themselves members of the tea party, and 28 percent generally support its agenda.

Tea party members scored a high-profile victory this summer, persuading Gov. Nathan Deal and legislative leaders to abandon a plan to move the referendum’s date from July 31 to the November 2012 election. Debbie Dooley, national coordinator of the Tea Party Patriots, said the proposed move amounted to voter shopping.

Bennecke says all voices are welcome, and the campaign will eventually come on strong — though he won’t say when. He said it must be careful not to start too soon and risk peaking too early.

The campaign has stumbled, losing Bennecke’s original lead partner, Glenn Totten. The temporary name for the tax effort, “T-SPLOST,” has seen most of its potential website addresses — such as tsplost.info, tsplost.org, tsplost.com — snapped up for a pittance by opponents or project advocates.

But the opponents have a tougher job than they did when the suburbs rejected mass transit, Coker said. New voters from transit-friendly cities throng the suburbs, and so do more cars and congestion.

“Atlanta 30 years ago was a different world,” he said. But with so much uncertainty in the months before the vote, all bets are off, he said. “A lot can happen over a 10-month period on something like this.”