Gov. Mike DeWine is proposing that the entirety of his requested 18-cents-a-gallon increase in the gasoline tax to maintain and upgrade Ohio's roads and bridges be imposed all at at once on July 1.

Prior increases in the gas tax have been phased over a few of years. In his transportation budget submitted Thursday morning to the House Finance Committee, DeWine also asked that the gas tax be indexed to increase annually by the rate of inflation to avoid erosion of its buying power.

The first-year Republican's request represents an 64-percent or $1.2 billion annual increase in the 28-cents-a-gallon gas tax, with DeWine billing the new money as vital to maintaining safe roads and protecting Ohio's economy.

An Ohio motorist with a vehicle that averages 30 miles to the gallon and who drives 15,000 miles annually ultimately would pay an extra $90 a year if DeWine's requested increase is approved by the General Assembly.

The owner of a semi-tractor that averages 6 miles per gallon of diesel over 25,000 miles of driving would pay an additional $750.

On Tuesday, DeWine said his requested gas tax increase would simply maintain the status quo of proper highway maintenance and some major projects without tacking on money for a fleet of wish-list projects.

The proposed increase would raise $725 million a year for the state's highway and bridge network while generating $480 million a year for local government street needs.

“You have to have a gas tax increase, there’s no doubt,” DeWine said Wednesday. “The day of reckoning is finally here and we have an obligation to face that.” Rising construction costs and inflation have combined to reduce the buying power of the gas tax dollar to 58 cents since 2003, state officials said.

Advocates for the tax hike point out Ohio's gas tax has not been increased since 2005 — with its 28-cent total placing Ohio's rate 29th in the nation — while every surrounding state has increased its gas tax since 2014.

“It is sorely needed,” said Rep. Gary Scherer, R-Circleville, vice-chairman of the Finance Committee. “I don’t know if that’s the right number or not. I’m not opposed to the conversation.”

Rep. Adam Miller, D-Columbus, said he is concerned about the regressive nature of the gas tax — meaning it has a bigger impact on lower income Ohioans.

“For my constituents this would really hurt their family budgets,” he said. “I’m a very hard sell on this.”

Transportation Director Jack Marchbanks, who testified Thursday morning in support of DeWine's budget proposal before the House Finance Committee, again stressed the dire need for additional revenue.

"Due to flat revenues, highway construction inflation, and mounting debt payments, ODOT is in jeopardy of being unable to fulfill its mission," he told the Finance Committee. "The credit cards are maxed out and the long-term health of Ohio’s transportation system is now at stake."

Ohio has the nation's fourth-largest interstate system and the second-biggest inventory of bridges in the nation.

"We think we are making a responsible request," Marchbanks said.

The transportation director said if inflation remains the same, the total 46-cent-a-gallon gas tax would increase to 54 cents by 2030 because of the indexing.

Rather than a pay-as-you-go approach, Ohio has sold bonds and borrowed money against future gas tax revenues and Ohio Turnpike tolls, Marchbank said. He also stressed on Thursday that the Department of Transportation has worked to be leaner operation, reducing 700 positions since 2011.

The borrowed money has run out to finance maintenance and improvements while debt repayments will consume $390 million in the coming fiscal year, he said. None of the borrowed money has been shared with cities and counties.

The Republican-controlled General Assembly has not seemed enthusiastic about increasing the gas tax, but leaders have promised it full review.

The DeWine administration has said there is no other option on the table to generate new highway funds beyond increasing the gas tax.

Ohio's local government officials, the trucking industry and a wide array of groups have lined up to support the proposed hike.

Motorists also pay a federal excise tax of 18.4 cents per gallon on gasoline and 24.4 cents per gallon on diesel. The federal tax, which is not indexed to inflation, last was increased in 1993.

Ohio House Democrats and others have called for increased state investment in public transit, but gas tax revenues only can be spent on roads and bridges under the state constitution.