While Durham officials circle their wagons and privately mull how to come up with another $2 million to build a pivotal pedestrian bridge over I-40, thereby completing the 22-mile American Tobacco Trail, others outside the city are more candid with possible solutions.

Durham discovered the shortfall in July when it opened bids from eight contractors on the project, which also calls for about 4 miles of paved trail. The lowest bid, from Blythe Construction, came in at $7.75 million, about $2 million more than the $5.8 million — including $4.7 million in NCDOT funding — the city has allotted. The shortfall has discouraged and annoyed — but not surprised — regional greenway advocates and users: As far back as 2007 the city estimated the project could cost as much as $6.3 million.

Asked Wednesday how what options Durham might have to bridge the gap, project manager Byron Brady and Dale McKeel, the proactive coordinator of Durham’s bicycle and pedestrian program, both said they were “not at liberty to say.”

On the other side of the Triangle, however, Triangle greenways uber-advocate Sig Hutchinson was not so constrained.

Hutchinson believes the bridge could be bundled with pending greenway projects in Cary and Raleigh to qualify for federal TIGER 3 funds. TIGER 3 involves transportation-specific funds available under the American Recovery and Reinvestment Act, the federal program launched two years ago to help dig the economy out of a black hole. $20 million in TIGER 1 funds, for instance, helped Raleigh fast-track the 28-mile Neuse River Greenway, the initial 8 miles of which is scheduled to open in September. The entire project is scheduled to be completed in 2013.

“As soon as I heard about the Durham bridge, I called called Vic [Lebsock, Raleigh’s senior greenway planner] and Doug [McRainey, parks planner for the town of Cary] to see about Tiger 3,” Hutchinson said yesterday.

Among the various requirements for Tiger 3 funds, a project must already be designed and shovel ready — meaning construction can start within 30 days of receiving funds — and an application must include a minimum of $10 million in projects. Applicants must also have a minimum of 20 percent in matching funds. Raleigh and Cary both have at least one key project that can be thrown into the mix.

Raleigh: Thanks in part to those Tiger 1 funds, Raleigh is in the midst of a greenway construction boom. In addition to the 28-mile Neuse River Greenway, the city is building the 3-mile House Creek Greenway, which will link the 15-mile Reedy Creek/Rocky Branch/Umstead B&B trail system with the 11-mile Crabtree Creek Trail; the last 4-mile stretch of the Crabtree Creek Trail, which will link the existing 11 miles of greenway with the emerging Neuse Trail; and a 2.9-mile stretch of the Walnut Creek Greenway. That will lengthen Walnut Creek, which runs along the southern edge of Raleigh, to 6.7 miles, but still leave it a mile and a half short of connecting with the Neuse River Greenway. It’s that last 1.6-mile stretch that Raleigh would seek Tiger 3 funding for.

Cary: Cary’s White Oak Creek Greenway is 2 miles short of connecting with the American Tobacco Trail. That stretch has been problematic according to Doug McRainey, Cary parks planning manager, because it’s actually in Apex and Apex hasn’t expressed much interest in the project.

“It’s north of their population center,” says McRainey. Besides, Apex is pushing to make its own ATT connection along Beaver Creek to the south.

Cary sees the 2 miles as key to its own system because the ATT connection would make it possible to take the White Oak Creek Greenway to Bond Park, where travelers could pick up the Black Creek Greenway for the 7-mile trek on to Lake Crabtree. There 5 miles of trail in adjoining Umstead State Park links with Raleigh’s Reedy Creek Greenway.

The TIGER 3 application process encourages bundling of interrelated urban projects, which would seem to bode well for a Cary/Durham/Raleigh package. Boding not-as-well is the fact that part of the package — the White Oak Creek element — is more rural than TIGER 3 likes to see for its urban applications. McRainey says that partially derailed a joint application between Raleigh, Cary and Wake Forest, among others, for TIGER 2 funds. There’s also plenty of competition for the $527 million in TIGER 3 funds available, with upwards of 200 applications expected.

Still, among the options being openly discussed, it offers hope for a community teased with the prospect of a bridge over I-40 for more than a decade.

“It’s a potential solution,” says Hutchinson, who says the bridge plays a key roll in the development of a Trianglewide greenway network.

“It’s huge,” says Hutchinson. “When you start thinking about the missing links in the system, you’ve got that one, White Oak Creek, the quarry, Walnut Creek and the Neuse. Everything else is just spurs connecting to the grid.” Plug in these missing links, complete that grid and a formidable secondary transportation system will exist for non-motorized travelers in the Triangle.

Applicants have until October 31 to apply for TIGER 3 funds.

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Follow-up post: ‘Could a TIGER save Durham’s American Tobacco Trail Bridge?’