Three big decisions remain to be made, as summarized at the end of yesterday's meeting by co-chair George Cianciolo of Chapel Hill. The first: Rail or bus in the "linchpin" corridor. Second: The overall scope of the plan. And third: How to pay for it.

And if that sounds like the entire job of the STAC is still in front of it as the Oct. 31 target date for finishing passes by, well, yes it is; on the other hand, a lot of information about potential routes has been digested by the group over the course of six months and 10 meetings to date.

The first question is a huge one. The ill-fated TTA plan was to start off transit in the Triangle with commuter rail service in the Durham-to-Raleigh corridor, which is shared now by Amtrak and freight trains. The corridor is owned by the N.C. Railroad Co., which is run as a private corporation—with its own board of directors—though it is wholly owned by the State of North Carolina. TTA was going to rent enough space in the corridor to build its own tracks, and was in the process of acquiring the adjacent properties it needed for stations, when federal funding for its plan fell apart.

But Durham-to-Raleigh is still considered the linchpin of any regional transit plan—and indeed, the planners have started calling it "the linchpin" because "Durham-to-Raleigh" sounds like it's leaving out the Carys, the Chapel Hills and others whose money will be needed to make a regional plan fly. So the question now is: Stay on course for rail service in the corridor someday, when federal funding is available? Or go for some kind of rapid-transit bus service instead, which would require buying up some other land in the corridor?

The basic idea of the bus alternative is to parallel I-40 in dedicated lanes and/or wholly separate corridors. In its own lanes, bus service could be as fast as trains. But if it's ever forced onto I-40 itself, or any of the other congested roads around it, it could slow to a crawl.

One big tradeoff, according to transit planner Patrick McDonough, who works for TTA: Bus service could be launched in segments and would be cheaper to run initially; but long-term, additional riders drive the cost of bus service up (more buses, more drivers), whereas additional riders drive the cost of rail service down. So in the long-run, it's likely a commuter-rail service would be more efficient.

The STAC is trying to put together a long-term regional transit "vision" that includes—someday—connections to fast-growing places like Northern Durham, Apex, Wake Forest, Zebulon and Clayton. But what routes to use, and more to the point, what "technology"—rail, bus, buses in dedicated lanes—is contingent in most cases on what's running in the linchpin corridor, trains or buses.

And costing the whole thing out is dependent on the above decision.

At which point, Cianciolo said, the STAC is supposed to tell local and state decision-makers how to pay for it. There's a good chance the STAC will say that Wake, Durham and Orange county voters should be asked to approve a dedicated tax for transit, probably akin to the 1/2-cent sales tax adopted in Charlotte-Mecklenburg to fund its transit system. That would require, first, approval by the General Assembly, since local governments in North Carolina can't do anything tax-wise until the legislature OKs it.

And everyone's watching closely for the outcome of the vote in Mecklenburg County next week, where conservatives are trying to get voters to repeal the 1/2-cent transit tax. So far, polls have the repeal effort losing, which would bolster the STAC's case here, no doubt.

Expect the basic decisions on this by December, Cianciolo said yesterday. But the exact shape of a tax recommendation will probably not be made until January.