BOSTON -- In its ongoing effort to figure out how to raise enough revenue to dig the state's transportation system out of billions in red ink, Massachusetts Gov. Deval Patrick is now floating a plan to raise vehicle registration rates for gas guzzlers.

The idea would be to charge higher registration fees for vehicles like Hummers while at the same time offering discounts for more environmentally-friendly cars, such as hybrids.

Eight other states currently offer tax breaks for people who buy hybrid vehicles, Massachusetts officials said. The idea drew positive reactions from some motorists.

"It's a good idea. It's the only way to wean us off gasoline," Boston resident Dave Guerin said.

The proposal is the latest offered up by the Patrick administration in its quest to find a palatable way to raise billions in transportation funds and encourage motorists to use more fuel-efficient cars.

So far, the governor's office has pitched a variety of plans, including higher toll fees for drivers using cash on the Massachusetts Turnpike, and a hike of 5 cents to 29 cents on the statewide gas tax. Also proposed: higher tolls for roads, tunnels and bridges -- in some cases up to $7 for the Boston Harbor tunnels.

At a business lunch, the majority of business leaders present told the governor they would support the higher gas tax rather than toll hikes, but many motorists said that doesn't work for them. Asked what they prefer ...?

"Higher tolls on the 'Pike, 'cause I don't drive on it," said a driver gassing up his car at a local station.

Other ideas floated by the governor have included imbedding chips in vehicle inspection stickers to replace Fast Lane passes and toll booths at the Rhode Island and New Hampshire borders and a new $6 per year Fast Lane transponder fee.

All of the proposals are aimed at paying down the Massachusetts Bay Transportation Authority and Massachusetts Turnpike Authority debts. The MBTA has $5.1 billion in debt, while the Turnpike has $2.3 billion in debt, much of it from inherited repayments costs for the $15 billion Central Artery project.

The plans also have called for streamining the state's various transportation agencies into four divisions that would include Highway, Rail and Transit, Aviation and Port, and the Registry of Motor Vehicles.

It is unclear whether the governor supports higher tolls or higher gas taxes. He has said he does not support both.