Come April, a new tax will be imposed in Salt Lake County to build three new rail lines and fix an interstate highway.

The Salt Lake County Council on Thursday voted to impose a quarter-cent sales-tax increase throughout the county, finishing a chapter in a six-month-long battle between state and local leaders over how to spend the money. County mayors endorsed the imposition of the tax earlier this week.

But Thursday's vote is not the end of the story. There could be problems in the upcoming legislative session, because some lawmakers believe the county is spending too much on transit and ignoring roads.

The governor's budget includes $449.7 million in new money for transportation, but lawmakers have the right to add or subtract funding from that budget.

Utah Department of Transportation officials said Thursday that top needs for funding include small projects such as widening 5600 West in Salt Lake County — something that costs little to fix but has a significant impact on congestion, said UDOT deputy director Carlos Braceras.

More expensive priorities include improving I-15 in Utah County and funding the proposed Mountain View Corridor.

But House Speaker Greg Curtis, R-Sandy, said that because Salt Lake County is spending 95 percent of the sales-tax money on transit, lawmakers may be reluctant to give more money to the county and the UDOT to fix, widen and improve roads.

"It will be very, very difficult for legislators when they (the county) come up and say, 'We need to meaningfully address transportation: Find us another funding source,"' Curtis said Thursday.

Over $2.5 billion of the Salt Lake County sales-tax money will be spent to build commuter rail, extend TRAX to South Jordan and West Valley, and fund improvements to I-80 between State Street and 1300 East. Construction of the transit lines is expected to start next year and finish within 10 years. Work on I-80 could begin as early as 2008, UDOT said.

By approving the tax money to fund the two light rail lines, Utah Transit Authority officials said that other tax dollars would be freed to finance new TRAX lines to Draper and the Salt Lake City International Airport. Those lines are also expected to be built within 10 years.

Members of the Salt Lake County Council said they were pleased that all four TRAX lines would be built, although they admitted that the process of getting authorization for the tax increase was ugly. By law, the county needed legislative approval to impose the sales-tax hike.