A list of transportation projects that voters will consider at the ballot box this summer would add $34.8 billion to the region’s economy over the next three decades, according to figures released Thursday by the Atlanta Regional Commission.

This summer, the 10-county Atlanta region is scheduled to vote in a referendum on a $6.14 billion list of transportation projects and a 10-year 1 percent sales tax to fund them. The projects include interstate interchange expansions, major mass transit lines, road widenings and MARTA repairs. An additional $1 billion raised would go to local governments for transportation improvements.

Opponents of the referendum questioned ARC's objectivity.  ARC, which provided staff for the “roundtable” of local elected officials that drew up the list, spent months testing those projects in its massive computer models and said the results were objective. It looked for the impacts of the project list, comparing the future transportation grid with the projects against the future grid without the projects. Its predictions include:

  • An overall increase of $34.8 billion by 2040 in the goods and services produced in the region.
  • An average increase in the region of 7,120 jobs per year from 2013 to 2040, both jobs to build the projects and jobs that come here as ripple effects from having better transportation. More than half would be in high-paying sectors. More than a quarter would be in construction.
  • Collective savings of $9.2 billion over the next three decades in travel time. That includes both savings in fuel and car repairs, and a dollar amount for how people value their time.
  • Overall, an increase of $18 billion in income people receive by 2040.

While others may use the numbers to sell the referendum to voters, ARC staff may only educate, not advocate. Opponents of the referendum don't think this rule has been followed in practice.

Bob Ross, co-founder of the Fayette County Issues Tea Party, said he respected ARC’s staff and computer models, which are commonly used by government and private industry to analyze transportation impacts. “But in terms of the leadership over there, I think they’ve got a clear agenda to make this seem as reasonable as possible to the population,” he said. ARC Chairman Tad Leithead did not return a phone call seeking comment. ARC staff said their analysis was unbiased.

Ross alleged that ARC was choosing not to model impacts that could cast a dim light on the referendum, such as the number of cars taken off the roads by the transit projects -- or a comparison of the actual project list to a hypothetical, better project list.

Mike Alexander, ARC’s research division chief, said the cars number would take longer to produce but is coming.

As to modeling a different list, he said, the roundtable’s instructions were only to model the actual one. In addition, modeling another one would take more months and resources when there is no settled hypothetical list to model.

An official with the referendum campaign said the results were helpful to its effort, but also accurate.

"It’s a big help to us as we explain what will be the result," campaign spokesman Bert Brantley said. "If anything, they know these numbers will be looked at and scrutinized, and I would say they're actually very conservative."