From widened roads to expanded I-285 interchanges to new suburban rail lines, cities and counties across metro Atlanta have presented a $24-billion wish list that could transform the way we move and live.

The projects could change the region on a large scale, linking formerly isolated suburbs in Gwinnett and Cobb counties to MARTA with rail lines.

And they could touch our lives in smaller ways, too, sprinkling commercial and entertainment centers across the region with sidewalks and bike paths that provide a mass transit-friendly lifestyle.

In 2012, some of the ideas will go before voters in a referendum that could provide unprecedented funding for transportation.

To get there, though, voters in the region’s 10 counties and 68 cities will have to do something they’ve never done before: vote together as a region.

The historic vote was set up by a new law last year that divided the state into 12 regions. Voters will decide whether to approve a 1-percent sales tax to fund transportation projects in their region.

Atlanta Mayor Kasim Reed called this “the true beginning” of the referendum process.

The Atlanta Regional Commission, which is overseeing the first step in the lengthy process, said it would take several days to have a reliable dollar total, because overlapping items were certain to appear.

Still, it was clear the cost of the desired projects far exceeded the $8 billion likely to be made available.

While there is opposition to the referendum, with local tea party groups mobilizing against the tax, just about every corner of the region wants something.

Gwinnett County, spurred on by business groups, requested a $1 billion rail line from Gwinnett Arena to MARTA’s Doraville station.

The city of Atlanta has requested $1 billion for the BeltLine. MARTA plans to ask for $1.7 billion to build mass transit lines and stations along eastern I-20.

Highway interchanges that cost more than $100 million for Ga. 400 at I-285 and western I-285 at I-20 also were submitted.

Under guidelines already approved, 25 to 80 percent of the money would be spent on roads; 15 to 60 percent on mass transit; and 1 to 5 percent on sidewalks and bicycle paths.

Deciding which projects to cut will be a tricky political task. If the right projects aren’t included, regional officials are convinced the referendum will fail.

“All it’s about is that list,” State Rep. Mike Jacobs, R-Atlanta, said at a referendum rally this week for a “fair share” for transit from the referendum. “Failure is not an option.”

Polls have already shown the referendum can’t pass without strong support in Fulton and DeKalb counties. Mayors in those counties have expressed concern that insufficient support for mass transit will doom the vote there.

Norcross Mayor Bucky Johnson, who leads a roundtable executive committee that will initially pare the list, said mayors and commissioners will have to view this process with a regional approach.

Under the guidelines, the projects have to benefit the region: There can be no sidewalks or driveways to nowhere.

Have your say

The Atlanta Regional Commission expects to consolidate all the requests into a single regional list by April 15.

After the roundtable comes up with a draft list in August, the region will hold meetings, perhaps one in each county, to gather public reaction.

People already can share their opinions by sending an e-mail to info@atlantaregionalroundtable.com, and each meeting of the roundtable will begin with 10 minutes for public comments.

Reed, who sits on the roundtable, said he had faith that the region could work together to treat everyone fairly, and create a list of projects that voters could support across the region.

Leaving the transit rally, Reed still sounded a note of caution, saying, “There is a belief that this is going to be easier than it is.”