LEHI — Extending the Mountain View Corridor and TRAX Blue Line south to Lehi were once thought to be aspirational plans that were decades away.

But now with a proposed $2.5 billion funding plan unveiled Thursday, construction could start in just a couple of years.

Both projects have been viewed as effective options in the efforts to accommodate the ongoing explosive population growth in and around the Point of the Mountain area and ease already daunting commuter challenges around the border of Salt Lake and Utah counties.

If pursued, funding to build out the Mountain View Corridor to Lehi, via the current Draper prison site and extending the TRAX Blue Line south to Lehi from its current terminus in Draper, could move construction start dates up to as early as 2021 and 2022, respectively.

Extending Mountain View and the Blue Line to points south has been prioritized through work being conducted for the past two years by the Point of the Mountain Development Commission.

The commission was launched by the Utah Legislature to assess the impacts of the state's current, and projected, nation-leading population growth and attendant issues brought by that influx. The body's work has included conducting public outreach and retaining consultants and analysts to determine the best paths forward to address, as directed by state lawmakers, myriad growth-related issues — including higher housing costs, longer commutes, worsening air quality, fewer new jobs and lost wage growth.

Taking the TRAX Blue Line south has been on the planning horizon since the extension was completed in the late 1990s, and a good portion of the right of way extending south from Draper, on the east side of I-15, has already been secured by the Utah Transit Authority.

However, planners say there are some good reasons to consider a west side route, that would head south from the Sandy City Station, run through the soon-to-be-redeveloped Draper prison site and then hook east to Lehi.

Mary DeLoretto, UTA's director of capital projects, said her agency has commitments covering over $600,000 of the expected $800,000 it will cost to conduct a yearlong alternatives analysis aimed at determining which TRAX alignment makes the most sense.

"The outcome of that will be a locally preferred alternative," DeLoretto said. "We'll gather public and stakeholder involvement to be sure to get everyone's input."

DeLoretto said the study will zero in on the capital, and operating costs, associated with both versions of taking the Blue Line south. Rough estimates now, per UTA, are $850 million to $950 million for the east route and $1.2 billion to $1.3 billion for the west side alignment.

While the east route is cheaper, the ridership estimates of 33,000 to 46,500 per day skew slightly lower than the west, which estimates show could draw 43,000 to 44,700 riders each day.

The commission's co-chairman, Rep. Lowry Snow, R-Santa Clara, noted that conducting the study doesn't necessarily mean that the project will happen.

"The purpose of the alternatives analysis is to see whether or not this even makes sense," Snow said. "Whether we proceed beyond that point remains to be seen."

An analysis done by Zions Bank Public Finance, which looked at dozens of potential funding mechanisms, highlighted six options that could be used to generate the estimated $186.5 million that would be needed by 2028 to service bond debt on both projects.

Those six options include:

• Implementation of a local option transit sales tax (0.20 percent) by Salt Lake and Utah counties, estimated to produce $70.3 million in the first full year of implementation.

• Implementation of a 0.25 percent transit sales tax by Salt Lake and Utah counties, estimated to produce $91 million per year in the first full year of implementation.

• Broadening the statewide sales tax base by 20 percent while lowering the tax rate by only 17 percent, estimated to produce approximately $102.2 million per year in the first full year of implementation.

• A capture of tax increment within the Mountain View Corridor. The analysis by Zions estimates that 75 percent of the increment within the corridor could produce approximately $1.84 million in 2021, growing to $7.8 million in 2024 and up to $19.9 million by 2028.

• A capture of tax increment within Blue Line TRAX zone. The analysis also estimates that 75 percent of the increment within such a zone could produce approximately $1.87 million in 2021, growing to $7.83 million in 2024 and up to $26.2 million by 2028.

• A capture of tax increment within the redeveloped 700-acre Draper prison site. Approximately 75 percent of the increment in this area could produce about $1 million in 2021, growing to $3.6 million in 2024 and up to $9.7 million by 2028.

The way the increment capture would work is a snapshot of property taxes would be taken at the beginning of the process and the "captured" new revenues would come from the increases that result from the projects' economic boosts to the areas, according to the analysts.

A commission report cited costs of taking the Mountain View Corridor to Lehi as about $1.3 billion. Under the proposal presented Thursday, the various funding options could be combined to service debt on UTA sales tax revenue bonds to pay for the TRAX extension and state of Utah general obligation bonds for the Mountain View Project. State statute limits terms of its bonds to 15 years.

There is also the possibility to secure federal transportation funding to offset costs of either, or both, of the projects. That pathway forward requires another level of federally required processes, including navigating the requirements of the National Environmental Policy Act, which would add time to the efforts, but could potentially lead to federal funding to offset as much as half of the costs, according to planners.

Ultimately, Utah lawmakers will be the decision-makers about how, or if, either or both of the projects get funded. Changes passed by legislators in the 2018 session via SB136 made substantive changes to UTA's governance structure and also created new options for funding large projects, including the transit reinvestment zones favored by analysts.

Data released previously by the commission has outlined various outcomes it says would play out if no actions are taken to accommodate expected growth in the area, which includes 1 million new residents headed for Utah County in the next 50 years. Those outcomes include rising housing costs, the loss of 150,000 future jobs, wage stagnation, air quality degradation and much worse commute times.

Draper Mayor Troy Walker, whose community is directly impacted by both the TRAX and Mountain View extension projects, expressed his hopes that the alternatives analysis would look at a full scope of transit solutions.

He noted that time is of the essence.

"It’s my hope that we’re going to look at everything," Walker said. "A combination of light rail, bus rapid transit and FrontRunner. I hope that our goal is to get the absolute best bang for our buck.

"We’re behind the eight ball on transportation a couple of years already. I think the time for action is now."