Katherine Kupukaa of Mililani is living on a fixed income, so she must be frugal in her spending.

And yet, state lawmakers are considering raising some of her expenses — specifically, three regarding motor vehicles.

“With Hawaii’s cost of living, it is appalling that you keep on adding costs to the citizens of the state just because we are able to afford a car,” she told a Senate panel Monday.

Kupukaa did not get her way, however.

The Senate Transportation and Energy Committee approved a bill that would hike the state fuel tax, the motor vehicle registration fee and the vehicle weight tax. The reason: to fix Hawaii’s highways.

Ford Fuchigami, director of the state Department of Transportation, told senators that his agency needs $100 million in additional funding for the state highway fund. Without that the money, roads, highways and interstates will continue to deteriorate, he said.

Fuchigami made an analogy with a leaky roof: The sooner the shingles can be replaced as part of routine maintenance, the less costly it will be to the homeowner.

Senate Bill 1012 will continue to move through the Legislature, but its prospects are uncertain. A similar proposal from Gov. David Ige’s administration did not survive last session.

Senators are also expected to hear a measure Wednesday that has been dramatically expanded beyond extending Oahu’s tax surcharge to pay for rail.

That measure, Senate Bill 1183, has been amended to direct an unspecified amount of money from the surcharge to help the highways fund.

At least one senator who voted in favor of SB 1012 on Monday voted with reservations. Sen. Breene Harimoto told Fuchigami that, while he understands DOT’s financial challenges, his constituents feel the money seems to go into “a black hole.”

Harimoto asked for a list of DOT projects, something Fuchigami agreed to provide. But the DOT director also warned that a lot of his department’s expenses are tied to the unexpected, such as mudslides and deteriorating coastlines that impair roads.

Ultimately, SB 1012 was amended to diverge from the tax and fee increases levels sought by the DOT.

The fuel tax would be raised 10 cents, to 26 cents per gallon, rather than to the 22 cents sought by DOT. But the registration fee rate would grow by $5 to $50, instead of to $75.

Should SB 1012 survive, or similar measures that could also move through the Legislature, final details could be worked out in conference committee at the end of April.

Few people in Hawaii, visitors or residents, would quibble with the argument that many of the state’s highways are in bad shape.

As Kupukaa herself noted in her testimony, “When can we expect to drive on roads, highways and freeways and not get a jolt going into a pothole?”