Maine has become the latest in a growing string of states to propose adding registration fees for hybrid and electric cars to make up for tax revenue on the gasoline they don't use, or use less of.

But it's also part of a much smaller group of those states in which the fees are punitive: drivers of those cars pay more than the gas taxes paid by drivers of average new gasoline-powered vehicles.

A bill introduced into the Maine legislature (L.D. 1806) would let the state Department of Transportation impose fees of $150 on hybrid-electric cars and $250 on battery-electric vehicles.

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Those vehicles currently represent less than 3 percent of all vehicles on the state's roads. The new fees could raise up to $2.9 million, according to state statistics.

Maine's proposed fees would be the highest in the country; similar fees in the 18 states that have so far adopted them run from $30 to $100 on hybrids and $50 to $200 on electric cars.

The DoT's manager of legislative services, Meghan Russo, cast the issue as one of fairness in an interview with the Portland Press-Herald, which covered the proposal last Thursday.

Gas pump

Gas pump

"Owners of these types of vehicles are paying far less in the gas tax than other vehicle owners," she said, "and they are using the highway system just like any others."

To decide whether the proposed fees are reasonable, it's useful to do the math.

The fuel economy of the average new vehicle sold in the U.S. has been stuck around 25 mpg for four years now.

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The EPA assumes a vehicle will run 15,000 miles a year, meaning that new vehicle will burn 600 gallons a year of fuel.

Maine's state gas tax is currently $0.3001 per gallon, meaning drivers of that new vehicle will send $180 to the state each year.

Drivers of old, inefficient full-size pickup trucks that get perhaps 15 mpg contribute $300, while drivers of 35-mpg gasoline cars send only $129.

2018 Nissan Leaf

2018 Nissan Leaf

Those who average 50 mpg in their Toyota Prius hybrids pay $90 in gas taxes for covering 15,000 miles; their total under the proposed system would be $240.

Coverage of the proposal by the Press-Herald included reactions from hybrid and electric-car drivers, who largely felt targeted and punished by unjustifiably high fees.

“I feel like I am being punished if this bill goes through because I am doing the right thing," said a retired 72-year-old teacher who drives her 9-year-old Toyota Prius hybrid perhaps 25 miles a week.

The owner of a Kia Soul EV summarized the general sentiment when he said owners of such cars want to pay their fair share, but that road repair should be funded on a usage basis rather than via taxes on fuel.

A separate bill introduced last year included both higher fees for fuel-efficient and non-gasoline vehicles and an increase in the state gasoline tax.

The administration of conservative (and controversial) Governor Paul LePage has indicated to legislators that any increase in the gas tax will go nowhere.