Indiana is one of only a handful of states that levies a sales tax on gasoline, a big reason Hoosiers regularly pay some of the highest gas prices in the nation.

So when prices rise – as they have been doing lately, including a jump of about 30 cents to $4.15 a week and a half ago – Hoosiers get the extra jolt of paying more sales tax to accompany the higher price.

Add the 7 percent sales tax that applies to most purchases to the 18-cent state gasoline tax and the 18.4-cent federal excise tax, and that $4 gallon of gasoline includes about 62 cents for taxes – exceeded only by California, New York, Hawaii, Connecticut, Michigan and Illinois.

State lawmakers, particularly the Republican leaders, crow about lowering the state’s corporate income tax and brag about the property tax cap. One detail they mention less often is that one way they were able to cap property taxes is by moving some of the tax burden from owners of more expensive homes to people who pay sales taxes – rich, middle class, poor.

Remember that next time you fill up.

I’ve long wondered why a state that depends so much on the auto industry makes it so expensive to buy and drive a car. The gas tax and auto excise taxes don’t help, and that 7 percent sales tax is a double whammy – $1,750 to buy a new $25,000 car, and now around $4 for a 15-gallon fill-up. And think how many times a year you put gas in your car.

The gas tax is significantly regressive – a tax not based on ability to pay. In other words, it’s a tax that consumes a higher percentage of a poor person’s income than that of a well-off Hoosier.

But lowering or dropping the sales tax on gas carries its own problems. For one, Americans need to use less petroleum, and higher gas prices help that to happen. It would be nice, though, if some of the sales taxes or direct gasoline tax went to programs designed to promote alternative fuels or renewable energy. Instead, ironically, one tax that makes it harder to afford to drive – the 18-cent state gasoline excise tax – goes to build and maintain roads and streets to encourage us to drive more.

Yes, it would be nice to do away with the sales tax on gasoline. But some of the latest estimates show that tax brings in about $40 million a month to the state. Where would Indiana cut $500 million a year from the budget? Or, more likely, which taxes would Indiana raise by $500 million?

One consideration should be a graduated, or progressive, income tax, with higher levels of income subject to higher rates, similar to the federal income tax.

Of the 41 states that tax wages, only six others beside Indiana have a flat rate tax, and only Pennsylvania has a lower flat rate.

Consider the big picture.

Indiana makes it more difficult than more than 40 other states to buy a gallon of gasoline, a burden that falls far harder on Hoosiers with lower incomes. When Hoosiers go to buy gas or a car or diapers or a lawn mower, they pay a sales tax with a rate exceeded only by California’s – and the 7 percent sales tax is another regressive tax. Higher-end homes are much more likely to qualify for property tax cap – that’s property tax relief – than lower-cost homes. Hoosiers making $15,000 a year pay the same state income tax rate as those making $150,000 or even $1.5 million.

Looking at this tax structure, Hoosiers cannot help concluding that the majority of today’s Indiana lawmakers aren’t very worried about the tax burden facing lower-income Hoosiers. But they will take action from increasing the tax burden on their higher-income campaign contributors – even if that means transferring some of the burden from upper incomes to lower incomes.

In theory, perhaps the fairest tax is one only on income – the one most closely connected with ability to pay. But governments do need a variety of taxes to bring in revenue during various economic situations. During recessions, for example, income and sales taxes plummet, while property taxes are far more reliable.

The 18-cent state excise tax on gasoline is in some ways a user fee – people using the roads pay a tax that goes toward maintaining state and local roads and streets. But the sales tax goes toward general state obligations, including education.

The sales tax stood at 2 percent through the 1960s but was doubled to 4 percent in the early 1970s as part of Gov. Otis Bowen’s property tax reform. More recently, the sales tax has increased twice in the past decade, from 5 to 6 percent in 2002, and from 6 to 7 percent just six years later.

Each time, proponents talked about how painless that “1 percent” tax hike would be – without explaining that the 1 percentage point in 2002 was actually a 20 percent increase, and the 2008 increase was 17 percent.

Today, with that sales tax on gasoline bumping Indiana into the stratosphere on gas prices, it doesn’t seem so painless.