DENVER — The Regional Transportation District is about to select a consultant who will need to come up with some prompt answers about commuting options in the northwest Denver-Boulder metropolitan area, given economic conditions that have changed since voters first approved the FasTracks system more than eight years ago.

The Northwest Area Mobility Study is designed to develop consensus among the agency, the Colorado Department of Transportation and northwest-corridor stakeholders to decide what improvements would be cost-effective.

RTD issued a request for proposals in December and received five strong entries from would-be consultants. RTD staff has ranked its first, second and third choices, said Marta Sipecki, senior public outreach specialist for FasTracks, and a committee of the elected RTD board will consider its recommendations at a public meeting to be held at 5 p.m. Tuesday, Feb. 5, at RTD headquarters, 1600 Blake St., Denver.

Once selected, the consultant will need to work quickly. RTD wants the study to start in March and be completed in early 2014. That process will involve meetings with the public and stakeholders, Sipecki said.

“The consultant will be looking at issues such as segmentation — whether rail can be built in segments — as well as possible alignments of a rail extension of the North Line to Longmont and bus rapid transit opportunities,” Sipecki said.

Lines traveling north and northwest would be served by wider-gauge commuter trains instead of the narrower-gauge light rail trains that run on the south and southeast lines, Sipecki said. “There are more stops closer together on the existing lines, which makes light rail more appropriate,” Sipecki said. “Toward Boulder and Longmont, the existing tracks are wider — but also there are fewer stops, farther apart, so the commuter-rail trains could go faster and carry more people.”

The original FasTracks plan for service to Longmont, approved by voters in 2004, called for commuter rail along the U.S. Highway 36 corridor to east Boulder and then along Burlington Northern Santa Fe tracks to Longmont by 2014. However, diminished sales-tax revenue and higher prices triggered by an economic downtown, and costs for using the BNSF right-of-way that were much higher than anticipated, caused the district to scale back the plan, triggering the proposal for the North Line extension.

A unanimous Longmont City Council voted on Oct. 2 to recommend that RTD extend the North Line to Longmont via a route that would bypass Boulder — but also bypass BNSF’s steep cost for right-of-way. The council wants the new rail idea to come with no additional tax increase, and wants RTD to consider improving bus service to and from Longmont along the Interstate 25, U.S. Highway 287 and Colorado Highway 119 (Diagonal Highway) corridors.

RTD’s current FasTracks plan includes an 18-mile rail line which would stretch north from downtown Denver and run parallel to I-25 through Thornton and Northglenn to 162nd Street. If that line were to be extended to Longmont, it would have to pass through Weld County, which is not part of the transportation district. However, some Denver-to-Longmont regional express bus routes already run through Weld.

RTD hopes refinancing some debt will allow it to build the North Line from Union Station to 72nd Avenue sooner than expected. If financial market conditions remain constant and RTD receives timely approvals from local governments, according to the statement, the district can release a request for proposal within the next 10 months to build the first segment of the North Line. RTD is considering applying for federal grants to help fund the remainder of the North Line to 162nd Avenue, and whether regional partners could collaborate to fund a 50 percent match — amounting to approximately $250 million — if a grant can be secured.

This latest strategy will not negatively impact the availability of funding for other partially funded projects, according to a press statement.

Ground was broken June 28 for the first segment of the Northwest Rail Line near the site of the future Westminster Station in the 6900 block of Grove Street, near 71st Avenue and Lowell Boulevard. That 6.2-mile segment of the Northwest Line from Denver Union Station to south Westminster is scheduled to be completed in 2016.