The Federal Highway Administration has approved Utah's plan for a Mountain View freeway -- if the state can afford it.

The agency signed off on the state's environmental study and route for the western Salt Lake Valley and northern Utah County road, which won wide praise from environmentalists and health advocates for its inclusion of a parallel transit system and air-pollution filtration at nearby schools. If the Utah Legislature funds the $3 billion project, an eight-lane freeway will stretch along 5800 West from Interstate 80 in Salt Lake City to 2100 North in Lehi and link from there to Interstate 15. The plan includes a bus rapid-transit system running on its own lanes down the middle of 5600 West.

"The next big step now is the funding," said West Valley City Mayor Dennis Nordfelt, who urged state lawmakers to make it a priority this winter. "I'm hopeful that the Legislature will find a rabbit in the hat. The need justifies the funding."

The state scaled back its immediate plans and instead will start Mountain View as a four-lane expressway with traffic signals at major cross streets. The Utah Department of Transportation hopes to complete that much in the next two to seven years, depending on state budgets, spokesman Nile Easton said.

So far, the state has designated just $360 million toward the project, including a $290 million future bonding package approved by the Utah Transportation Commission and $70 million from corridor-preservation funds in Salt Lake County. The bond package includes $130 million for Utah County construction beginning next summer and $160 million for work and corridor preservation in Salt Lake County.

"Five years of collaboration has resulted in a balanced solution of roadway, transit and trails that fits within the framework of the communities," UDOT project manager Teri Newell said in a written statement.

The state also compromised with groups fearing the freeway's placement near several schools endangered children's lungs. UDOT will spend $3.1 million to filter air inside the schools and $1 million to monitor the air outside. It also will pay to relocate Hillside Elementary if school officials request that.

Those changes and the transit plan garnered support from the Sierra Club and Utah Moms for Clean Air, a marked contrast from the bitter fight surrounding the state's last major new highway. The Legacy Parkway in Davis County unspooled years of legal wrangling and, finally, a settlement that environmentalists said set the tone for future cooperation.

bloomis@sltrib.com