It’s not easy to get excited about the state’s excise tax.

Buyers of new cars get slammed with a high tax rate and another bill, due before the car can be registered. But the tax doesn’t end after the first year. It continues on with the life of the car, diminishing along with the vehicle’s value.

A bill that was presented to the Taxation Committee last week would change the way the tax is levied. L.D. 345, An Act to Base the Excise Tax on Motor Vehicles on the Purchase Price, would set the tax owed based on what a buyer actually pays for a car instead of the sticker price.

Because most people don’t pay the list price, the tax overestimates the “value” of the car or truck. Car dealers don’t like the way the tax is assessed. And it’s easy to understand why some people would support a change in the law that reduces tax liability.

Municipal governments would be the biggest losers if the bill were to pass. As the Maine Municipal Association reports, the excise tax funds construction and maintenance on 13,000 miles of Maine roadways. If the excise tax is restructured in a way that reduces revenue collection, that burden will fall to the property tax, or roads will be ignored. Neither option is good.

The Maine Automobile Dealers Association supports the proposal, but would like to see it changed so that it shifts more of the tax burden from new car buyers onto the owners of older cars. This change would be revenue neutral, protecting local revenue.

The tax should stay as it is. The fact that new cars are taxed at a higher rate than older ones adds progressivity to the system. People who can afford a new car can afford the tax bite more easily than a person driving an older model, who now typically pays less.

The excise tax is onerous. It comes all at once and is an easy target for taxpayers’ ire. But the current law treats car buyers around the state the same. It is progressive and finances important highway work. It should be left alone.