PROVO — Utah County elected officials are crossing their fingers to prove they aren't dragging their feet on transit.

The Utah County Commission is expected to vote as soon as today to put a quarter-cent sales tax increase on the ballot in November to fund a 22 1/2-mile commuter rail line from the Salt Lake County border to Provo.

If it passes a public vote, the tax increase would generate $765 million by 2030, according to projections by the Mountainland Association of Governments.

MAG, which coordinates transportation planning in Utah County, has recommended to commissioners that commuter rail be the top priority for those funds in order to give commuters a north-south alternative to I-15, hopefully in time for the planned freeway reconstruction as soon as 2011.

Commissioners are expected to commit about 90 percent of revenues from the tax increase to transit, including the estimated $300 million price tag for commuter rail construction in the county. Then they'll cross their fingers in hopes that Salt Lake County will follow suit and fund an additional $300 million for the 22 1/2 miles from the county border north to Salt Lake City.

A southern commuter rail line is in the long-range transportation plan for Salt Lake County — but there are no guarantees it will accommodate Utah County's I-15 reconstruction mitigation plan. Currently, no funding exists to extend commuter rail from Salt Lake City to the Point of the Mountain.

Utah County officials are hoping to have an interim commuter rail system using the existing Union Pacific freight line up and running by 2011 and permanent service by 2014.

"If we look at the question of reconstruction of I-15, if we go from eight lanes down to four, we'll have 24-hour gridlock for five or six years, without commuter rail," Commissioner Steve White said.

Utah County had hoped to have more solid assurances from Salt Lake County on commuter rail before taking this leap of faith, but that hasn't happened, said Chad Eccles, MAG's transit planner.

"We've just come to a point where we need to do something," Eccles said. "Maybe (Salt Lake County officials) are waiting for us to act. If we come to them with money and ready to do our project, maybe that will put some emphasis on others to work to meet us there."

Darrell Cook, MAG's executive director, said he's optimistic that Utah County's taking the first step will motivate the other players to move forward on a commuter rail line connecting Salt Lake and Utah counties.

"We wouldn't go so far as to take the first step if were weren't confident that everything is going to come into place in a timely fashion to make this work," Cook said. "We wouldn't take that kind of risk."