INDIANAPOLIS (AP) — Poll results released Monday indicate that most Indiana residents approve of a 10-cent fuel tax increase enacted by the Legislature this spring to help fund statewide infrastructure projects.

Ball State University's Hoosier Survey found that about 57 percent of participants approved of the tax increase and about 38 percent disapproved.

The tax hike was passed by the Republican-dominated Legislature and signed into law by Republican Gov. Eric Holcomb as part of a package of tax and fee increases that pumped money into the state's crumbling roads and bridges.

It was most popular among those ages 18 to 34, with 65 percent of such respondents backing it. It was least popular among those 55 or older, with 51 percent supporting it and 43 opposing it, the survey found.

Geographically, the increase was most popular in southern Indiana, where 63 percent of adults favored it.

The results released Monday are the latest from the annual poll, which surveyed 600 Indiana adults by phone between Oct. 2 and 15. The university has been dribbling out results, with more expected, addressing issues like the state's prohibition of Sunday alcohol sales and its lack of a hate crimes law.

The poll has a margin of error of plus or minus 5.3 percentage points.

The gas tax findings come amid a blitz of appearances by Holcomb, who since summer has touted new money for roads projects during news conferences held across the state.

While the survey suggests most adults in Indiana support the increase, less clear is what it means for Republicans lawmakers who voted to approve the hike.

The group Americans for Prosperity recently launched a mail campaign targeting two key GOP lawmakers who helped shepherd the measure through the Statehouse. The group, the political arm of conservative industrialist billionaires Charles and David Koch, says the campaign is an "accountability effort to call out" GOP state Rep. Ed Soliday and state Sen. Michael Crider.

Republican Senate candidate Mike Braun, who is expected to step down from his Indiana Statehouse seat on Nov. 1, also supported the tax increase. It's a vote his Republican primary opponents aren't likely to let him forget.