A massive MARTA expansion. Loosened bottlenecks on I-285, other interstates and arterial highways from Cherokee to Henry counties. Sidewalks, bicycle lanes and maybe even a couple of airport projects in Cobb County.

Everything is possible — and nothing.

Monday is the deadline imposed by state law for the Atlanta region to draft a $6.14 billion list of transportation projects that would be built if voters approve a 10-year 1 percent sales tax in a 2012 referendum. Leaders have been at it for months without success. On Thursday, they missed a self-imposed deadline and put off their decision to the last possible moment.

Atlanta Mayor Kasim Reed said Thursday that in spite of the appearance of a bumpy road, “We have a process that is proving successful.”

Henry County Commission Chairwoman B.J. Mathis came out of the aborted meeting saying that, with such a momentous decision, delay was to be expected. “That’s government,” she said.

Reed and Mathis are on a 21-member “roundtable” of mayors and county commissioners that will approve a final list by Oct. 15, and they also are on the five-member committee that must approve the first draft by Monday.

It’s not clear what would happen if there is no first draft by the Monday deadline, or one that’s over budget; the state law that set up the referendum only says that the first draft must be done by Aug. 15. But the consequences of not having a final draft by Oct. 15 are spelled out, including not being able to hold another transportation referendum for two years.

Here are some highlights from the working list of 119 projects adopted by the roundtable Thursday. It adds up to $6.56 billion, $420 million over budget. There appear to be few options: cutting, swapping out or reducing some projects; or finding some other way to fund them.

Mass transit

● Clifton Corridor MARTA route to Emory University, $700 million

● Atlanta Beltline, likely streetcars, $658 million

● Atlanta to Cumberland (Cobb County) northwest corridor, possibly light rail, $879 million

● MARTA state of good repair funding (various upgrades), $600 million

● Restore Clayton County local bus service, $100 million

● Preliminary work on a possible light-rail line from Doraville into Gwinnett County, $100 million

● Georgia Regional Transportation Authority Xpress bus service, $180 million

● Eastern MARTA extension in I-20 corridor, $250 million

● Gwinnett express bus service, $40 million

● MARTA heavy rail extension north to Ga. 140, $37 million

Roads

The dollar amounts are what the sales tax would fund. In some cases other funds also would be used, like federal funds.

● I-285 at Ga. 400 interchange, $172.5 million

● I-285 at eastern I-20 in DeKalb County, $47 million

● Spaghetti Junction, $26.5 million

● Replacing Courtland Street Bridge in Atlanta, $22 million

● Tara Boulevard “super arterial” in Clayton, $130 million

● Widening Lake Acworth Drive from Cobb Parkway to Cherokee Street in Cobb, $29.1 million

● North Druid Hills Road from Buford Highway to Lawrenceville Highway corridor improvements in DeKalb, $25 million

● Interchange improvements at eastern I-20 and Panola Road in DeKalb, $10.6 million

● Improving intersections on Cobb Parkway from Barrett Parkway to Bartow County in Cobb, $9.8 million

● Widening Arnold Mill Road in north Fulton County, $46 million

● Widening Camp Creek Parkway from I-85 to Welcome All Road in south Fulton, $61 million

● Widening Five Forks Trickum Road in Gwinnett, $10.4 million

● Widening Ga. 140 in Cherokee County, $200 million

● Widening Thornton Road in Douglas County, $43 million

● Widening North McDonough Road in Henry County, $48 million

● Widening Sigman Road in Rockdale County, $30 million

● Building a new East Fayetteville Bypass, $50.8 million

Aviation

● New air traffic control tower at McCollum Airport in Cobb, $2.5 million

● Runway approach lighting system at McCollum, $690,000

Bike/pedestrian

● Buford Highway pedestrian, landscape and bus improvements in DeKalb, $12 million

● Lawrenceville Highway multi-use trail and pedestrian improvements in Gwinnett, $1.9 million