The county commissioners of both counties will be asked to approve the plan and put the half-cent sales-tax referendum on the November ballot.

Voters in both counties, however, already face separate proposals for a quarter-cent increase in their sales tax.

In Orange County, voters rejected that sales-tax increase last year. If they pass it this time, it would fund schools and economic development.

Given a tough economy and a long list of competing needs, it wasn't immediately clear at last Wednesday's committee vote whether the two counties would put the transit tax up for a vote this fall.

Bernadette Pelissier, chairwoman of the Orange County commissioners, said she was "comfortable" with urging her board to schedule the referendum.

Michael Page, the Durham County commissioners' chairman, said he wasn't sure the plan was a top priority.

"Right now it's really touch-and-go as to whether or not this will be able to move forward," he said.

The plan the Durham-Chapel Hill-Carrboro Metropolitan Planning Organization's transit committee approved calls for:

Beefed-up bus service in and between the three municipalities;

An electric-powered light-rail line from the UNC campus to East Durham;

The Durham County portion of a rush-hour commuter train line from West Durham to Garner.

Wake County commissioners and transportation planners also are considering proposals for the commuter trains and similar bus and light-rail improvements, but no decisions are expected this year.

Wake voters won't be asked to consider a transit sales tax increase before May 2012.

The Durham-Orange plan calls for expanded bus service in the first few years while design and construction work begins for the proposed light-rail line, which could open in 2025.

State and federal funds would be sought to help pay for the rail line.

"This will mean a huge increase in the public transit services we are able to provide," Carrboro Mayor Mark Chilton said. "Just the bus component of this plan is a huge, huge win for 95 percent of Orange County residents."

Durham City Council member Mike Woodard was hopeful about chances that county commissioners and voters will support the transit plan and a half-cent sales tax to help pay for it.

"The early polling numbers show that people do favor it," Woodard said.

Chilton said sooner is better than later for the transit plan.

"Talking about delaying further and further into the future would be a serious mistake," Chilton said.

Regional leaders say Durham and Orange can start work on bus and light-rail improvements without waiting for Wake County.