Legislative leaders announced a deal Friday with local developers to donate as much as $80 million in land on which to build the Mountain View Corridor in southern Salt Lake County — a move that will speed construction of the planned highway.

In addition, a plan was announced for a mass transit line along 5600 West in Salt Lake County, adjacent to a proposed route for Mountain View along 5800 West. The transit line has been a source of contention for environmental groups who have worried the state is building a pollution-producing highway without a transit option.

Marc Heileson, regional representative with the Sierra Club, said the transit news was encouraging. His group has threatened the state with future lawsuits if transit wasn't included as part of work on Mountain View, which is proposed to run 44 miles from northwestern Salt Lake County into Utah County.

"I think our main concern is balance," Heileson said. "I think there is a real solution out there where you put in transit immediately and then add road capacity where it's needed."

Officials with the Utah Transit Authority said they would begin buying land for the transit line within the next two years. It would begin as a bus rapid transit line, and then later be converted into a rail line, said Bruce Jones, UTA general counsel.

As for the land deal, it is contingent on the Utah Department of Transportation being able to start construction within the next five years on a 10-mile section of Mountain View from 9000 South to Redwood Road in Salt Lake County.

UDOT officials said they are committed and have funding to begin work on that segment once environmental studies are finished. Under the negotiated land deal, the state would also chip in money as an incentive toconstruction, which is estimated to cost as much as $586 million.

A new poll done for the Deseret Morning News and KSL-TV by Dan Jones & Associates shows residents support work on Mountain View but prefer reconstruction of I-15 in Utah County first.

The poll was of 412 people. It showed that 49 percent of Utah residents thought I-15 was a higher priority for construction, while 31 percent preferred that Mountain View be funded first.

The survey had a margin of error of plus or minus 5 percent. It was conducted Feb. 19-21.

Sen. Sheldon Killpack, R-Syracuse, said the Mountain View deal could still be done in conjunction with the reconstruction of I-15. Earlier this week, the Senate Republican caucus took a position to support the rebuilding of I-15 from 12300 South in Salt Lake County to U.S. Highway 6 in Utah County

"These opportunities just don't present themselves every day," Killpack said of the Mountain View agreement. Killpack and House Speaker Greg Curtis, R-Sandy, were the chief negotiators behind the transit and land deal.