As York County residents grapple with already high gas prices, they're not looking forward to a proposed gas tax becoming law.

Two U.S. senators last week called for raising the federal gasoline and diesel tax by 12 cents a gallon to keep the Highway Trust Fund from running out of money in August.

The bipartisan plan proposed by U.S. Sens. Bob Corker, R-Tenn., and Chris Murphy, D-Conn., would raise the tax 6 cents during the first year and 6 cents during the second year.

"If it's going to make gas prices higher, I don't want it," said Gary McCully, a 53-year-old Shiloh resident.

Every bit of the increase will be passed onto consumers at the pump, said Gregg Laskoski, senior petroleum analyst at GasBuddy.

"If the federal tax goes up, there's no masking it. It will be reflected immediately. There's a better chance of being struck by lightning than the cost not being reflected at the pump," he said.

State increase: If the proposal becomes law, the federal tax increase would come on the heels of a state tax increase.

A bipartisan transportation bill passed in November by Pennsylvania lawmakers lifted the limit on the wholesale tax for gasoline, which had been capped at $1.25 per gallon since 1981.

The new tax meant an extra dime to wholesalers this year and will grow to a 28.5 cents-per-gallon increase by 2018.

That will all be passed on to consumers, Laskoski said.

"Any tax is always passed on to consumers," he said.

The rationale: Both the state transportation bill and the proposed tax to fund the Highway Trust Fund are designed to improve infrastructure.

Because Congress hasn't raised the gas tax since 1993, and motorists are driving more fuel efficient cars, there has been less tax revenue to improve aging roads and bridges.

"It has shifted the burden to the state level," Laskoski said.

In the last year, eight states have raised gas taxes or passed new transportation bills.

"There's no question there's money needed at the federal level, as well as the state level, because we have an awful, lengthy history of roadwork being postponed. A lot needs to be done to bring our roads and bridges to safety," he said.

But motorists are more likely to see improvements to their local roads from the state tax.

"There's greater control over the money at the state level. It's easier to follow the money and demand transparency. It's wishful thinking for people to believe if they pay increased federal taxes they will immediately see benefits on Pennsylvania roads," Laskoski said.

Reaction: That's one of the reasons Anna Null doesn't want to see the tax pass.

"We're going to pay higher prices and still drive on the same crappy roads. There's a lot of talk, but nothing ever seems to get fixed," said the 46-year-old Dover resident.

How likely it is that consumers will see a bump at the pump is unclear. There are various proposals being floated by U.S. lawmakers.

U.S. Rep. Scott Perry, R-Dillsburg, doesn't support the proposal to raise the gas tax by 12 cents.

Perry, who sits on the House Transportation and Infrastructure Committee, said he's working with colleagues to come up with long-term solutions that make the country's transportation system safer and more efficient, while strengthening the economy and spurring job creation.

"All of us can see that our infrastructure is crumbling around us," he said. "We need to be smarter about our nation's limited transportation dollars."

U.S. Sen. Bob Casey, D-Pa., said he's still examining a number of funding options before making a decision.

"I think there are a lot of ideas that are going to be on the table for discussion," he said.

U.S. Sen. Pat Toomey, R-Pa., was not available for comment.