Gwinnett County commissioners have less than a month to approve a transit plan if they want voters this fall to have another chance to expand transportation options in the county.

The tight deadline leaves commissioners some wiggle room for deciding details about a potential penny sales tax — including whether it’s administered through MARTA or the new ATL board. But either way, county leaders must pass a transit plan by April 7 if they want it to be on the November ballot.

The actual deadline for calling for a vote is July 21, but Gwinnett will need to go through a process before then to update the regional transit plan with its new proposal and negotiate contracts, whether with MARTA or another operator. Any heavy rail must be operated by MARTA, but the county could continue to operate its own system aside from any heavy rail expansion.

Commissioners still aren’t sure if they want to expand heavy rail to Jimmy Carter Boulevard, as a transit review committee recommended. In addition to the committee’s proposal, they will look at a version of that group’s plan that eliminates heavy rail but has more frequent service. They will also consider a plan put forth by Commissioner Ben Ku that would begin to expand service regardless of the results of a vote, and they will look at the Connect Gwinnett plan that voters rejected last year.

“I’m not going to make any predictions,” Commission Chairman Charlotte Nash said of whether the group will meet the deadlines for making a decision. “We’ve got work to do, still.”

Ku said he hoped commissioners would agree on a plan in time for November, while Commissioner Jace Brooks said he was confident they would. Commissioner Marlene Fosque said she was open to possibilities regarding the transit plan and was waiting to see the final results of the discussion, which will resume March 26. Commissioner Tommy Hunter said he thought a measure would make the ballot, but he wouldn’t support it.

“Would appear the new MO in Gwinnett will be to vote until we get the result government wants,” he said in a text message to the AJC.

Over the next two weeks, consultants will go through the various proposals to better lay out for commissioners what they will be getting with each plan they might approve. There are trade-offs for reliability, frequency, mode of transportation and other factors that commissioners will have to consider, in addition to making sure whatever they approve is within the limits of what they’ll be able to fund and build.

“There’s a good bit of work involved in it,” said Alan Chapman, Gwinnett’s transportation director.

Depending on the funding route commissioners take, Gwinnett’s cities might also have a say in approving any proposals. The ATL board’s transit plan hasn’t been updated since it was first approved last year, so Gwinnett is the first entity to go through the process to amend the plan.

Commissioners are aware that there are deadlines that need to be met. Fosque said she was concerned about the time frame for finishing the analysis.

“This is really tight,” she said.

Nash countered that the commission had worked quickly to bring a MARTA proposal to voters last year, too. Still, Brooks said, “There is no time to dilly-dally.”

Nash said she’d found the discussion helpful, particularly as she learned what questions her colleagues still have. Ku said he thought the final decision would be a difficult one as each plan leads to different trade-offs, but that he thought the county had good options.

“The best plan is something that’s regionally focused, has connectivity and is scalable,” he said.