SALT LAKE CITY — State lawmakers plan to consider overriding a vetoed bill that they say could lead to a gas tax increase if it isn't reversed.

Utah House and Senate leaders called a rare override session after a poll of their bodies found more than two-thirds in favor of it. The session will convene on May 6 at 8 a.m. at the Capitol.

Gov. Gary Herbert vetoed four bills after the 2011 Legislature adjourned.

The one at the top of lawmakers' agenda deals with earmarking 30 percent of new growth in tax revenues to pay for transportation projects, which legislators see as a way to ensure Utah has the necessary infrastructure to encourage economic development.

Bill sponsor Sen. Stuart Adams, R-Layton, said that without SB229 legislators might have to raise the gas tax, an idea they rejected during the regular session this year. The 24.5 cents per gallon tax has not gone up since 1998.

"Before we look at raising any tax, we want to solve the problem within our own resources," he said.

The money would go to road maintenance and projects statewide including I-15 expansions, the Mountain View Corridor extension and the Southern Parkway in Washington County.

Herbert said in a statement Tuesday that he vetoed the legislation because it puts at risk Utah's ability to fund other critical needs such as education.

"Maintaining the responsible fiscal prudence for which Utah is acclaimed includes protecting budget flexibility," he said.

Adams said the state has taken hundreds of millions of dollars from the Transportation Investment Fund the past few years, including $110 million in 2010 for higher education buildings that Herbert wanted.

"If you really believe that limits (flexibility), you have to look at history because it hasn't," Adams said.

Lawmakers might also consider overrides of HB328, which would have put the state back on a five-day workweek; SB294, which would have changed health insurance plans and costs; and SB305, which would have used a Web-based tool to align schools with the needs of the business community.

Senate President Michael Waddoups, R-Taylorsville, said there might be discussion about those bills, but doubts there will be any action on them. Herbert has already agreed with lawmakers to provide extra public services on Fridays when most state offices are closed, allaying a challenge to his veto of the five-day workweek.