DETROIT - Automobile club AAA says there's no sense paying a premium for premium gasoline if your car is designed to run on regular.

The club did research showing that premium didn't increase horsepower or fuel economy. It also didn't reduce emissions or clean engines any better than regular gas.

Some drivers occasionally like to treat their cars to higher-octane fuel in the belief it boosts performance. Premium blends can cost around 50 cents per gallon more than regular.

But AAA says that's money out the tailpipe. In a national survey on gasoline use, it found that 16.5 million U.S. drivers spent $2.1 billion they didn't need to in the past year on premium gas.