Howard Ison, who for 10 years drove a tow truck all over the United States but mostly in Salt Lake County, reckons the county's TRAX light-rail lines upped his annual income from $50,000 to $65,000. "I've just seen how much better traffic was once [TRAX] started," he said.

So for him, voting for Proposition 3 is a natural - and he is in the majority, according to a Salt Lake Tribune poll released Thursday that shows 53 percent of county voters favor it.

If passed, the measure would raise the sales tax in the county by a quarter-cent to pay for transit and road projects. About $11 million of the expected $50 million annual revenues would go to buy land for the west-side Mountain View Corridor highway, with the rest of the money spread out over TRAX, commuter rail to Utah County and perhaps 23 small road projects.

The survey of county voters found 30 percent would vote against the measure, with 17 percent undecided, a relatively high number that Proposition 3 proponents say could be overcome with further explanations of how the tax money would be spent.

For Ison, though, the choice is clear. "We've got to get some mass transit in here and get stuff done now so it doesn't cost us millions [more] later," said the 53-year-old Salt Lake City resident. "I've seen the way other states have done it, and the way Utah does it, it's kind of a joke."

But Brenda Knowlden doesn't like taxes and won't vote for Proposition 3. "Every time we collect money for transportation we spend it on something else that seems more pressing," said the Riverton resident.

Proposition 3 grew out of a law passed during a legislative special session Sept. 19. The law says the ballot language must ask voters to approve the tax hike for "corridor preservation, congestion mitigation, or to expand capacity for a regionally significant transportation facility."

The measure started out as an $895 million property bond issue to complete four TRAX lines in Salt Lake County, but during the summer developed into a quarter-cent sales tax with an expanded number of projects. A Tribune poll in June showed 60 percent of respondents favored the property tax increase, meaning the current sales tax measure has less support.

The sales tax would raise about $50 million per year. About $11 million of that would be earmarked for Mountain View Corridor property purchases.

Supporters say that should Proposition 3 pass on Tuesday, transit and transportation projects on the table for 2030 completion will be accelerated, with some completed by 2015 or sooner.

Two other poll questions about the measure yielded results seemingly inconsistent with the aims of lawmakers who passed a law Sept. 19 allowing the tax-increase vote with a primary focus on two TRAX lines, commuter rail and the Mountain View Corridor.

Asked which projects they would put at the top of the list for construction, 45 percent of the Salt Lake County voters surveyed said they preferred all four proposed TRAX light-rail lines; 24 percent said commuter rail; and 26 percent offered other alternatives or said they were not sure. Just 5 percent said they favored buying land for future highways, including the Mountain View Corridor.

An earmark on Proposition 3 requires 25 percent of the revenues to go to regionally significant highway land buys, which at this time means just Mountain View Corridor.

Asked which new TRAX line they would like to see built first, 36 percent of the voters surveyed preferred the one to Salt Lake City International Airport; 19 percent wanted the line that would connect West Jordan and South Jordan with the existing north-south line; 17 percent favored the West Valley City line; 9 percent favored extending the north-south line to Draper.

The poll shows the lowest undecided percentage was for male respondents at 7 percent. Women, however, were 27 percent undecided, with 50 percent in favor and 23 percent against passage.

"We hope to be able to educate the undecided voters so they will be willing to join us," said Jim Bennett, Vote for 3 campaign manager.

In one sense, he said, a 53 percent majority this close to an election looks like a sure bet. But pollsters say issue campaigns, especially tax issues, aren't so easy to call.

"People who go in to vote to increase their own taxes may not be as eager once they actually face the ballot," Bennett says. "That's why we're not taking a 53 percent number for granted."

University of Utah political scientist Matthew Burbank said the poll results bode well for the measure. What the undecided numbers mean is unclear, however.

Burbank said that he was surprised the undecided number wasn't higher at this point. On the other hand, he said, "if going into Tuesday there's still that 17 percent undecided, probably more of those people will come out against it than in favor."