DENVER - The Regional Transportation District is preparing to conduct a study that will evaluate mobility options in the northwest Denver-Boulder metropolitan area, including a potential extension of the North Line to Longmont and bus rapid transit opportunities.

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.

A request for proposals was issued in December, and an RTD press statement said the district received five strong proposals in response. The selection of a consultant to conduct the study is under way, according to the press statement, and the chosen candidate will be presented for approval to the elected RTD board in February. The study is scheduled to start in March and be completed in early 2014.

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 the 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.