Gov. Dave Heineman has vetoed a bill that would have raised the gas tax by 1.2 cents a gallon. He’ll probably veto another bill that would raise the gas tax by 3.3 cents a gallon.

No surprise there. Heineman’s vetoes will be popular at a time when gas prices are at record highs and rising, perhaps to $4 a gallon by summer.

But it would be disappointing and contrary to the long-term interests of the state if Heineman also vetoes LB846, a bill introduced by Sen. Deb Fischer of Valentine, that would change the mechanism for taxing fuel.

That bill, intended to be revenue neutral, would rework Nebraska’s system for taxing fuel, exchanging 7 cents of the current fixed fuel tax for a 5 percent sales tax on the average wholesale price of gas.

That change would be an important improvement in the system because it would help revenue keep pace with inflation. The old per-gallon system doesn’t automatically adjust for cost of living increases.

It may surprise Nebraska motorists to learn they are actually paying less in gas taxes than they were 20 years ago, when adjusted for inflation. Last year, motorists in Nebraska paid an average of 27 cents per gallon in taxes. That would be equivalent to paying about 15 cents in 1987, when motorists were actually taxed 18 cents per gallon.

Road funds are drying up. The federal highway trust fund is scraping bottom. State officials expect federal road funding for Nebraska will drop about $80 million next year.

Meanwhile, the cost of road construction materials such as cement and steel, as well as the petroleum-based materials used for asphalt roads, continues to climb.

Growing Nebraska communities justifiably believe they deserve a bigger proportion of state road dollars. Lancaster County grew by 9.5 percent from 2000 to 2007, yet Lincoln continues to get back only 29 cents of every dollar its residents pay in fuel taxes.

An important thing to remember about the gas tax is that it goes strictly to road and street construction and repair. It’s not diverted to other uses. If you drive, you need a road, and you should pay.

The impact of the gas tax should be kept in perspective. A penny per gallon increase amounts to less than $10 a year for a driver who averages 18 miles per gallon and drives 15,000 miles a year.

Would it be worth $10 a year to get those potholes fixed, or maybe lengthen a turn lane so traffic doesn’t back up during rush hour?

Politicians like to take credit for holding the line on taxes, but they also should take the blame when there isn’t enough money to keep the roads in good shape.