American drivers are wasting a jaw-dropping $2.1 billion a year on premium gasoline.  That's according to new research from AAA, which reveals that purchasing pricey premium fuel is a waste of money — and offers no vehicle benefit — if you're driving a car designed to run on regular-grade gas.  Sign up for the free Money Talks Newsletter  AAA says in the past year, 16.5 million U.S. drivers have disregarded their vehicle manufacturer's fuel recommendation and filled up with premium fuel. John Nielsen, AAA's managing director of automotive engineering and repair, says in a statement:  "Drivers see the 'premium' name at the pump and may assume the fuel is better for their vehicle. AAA cautions drivers that premium gasoline is higher octane, not higher quality, and urges drivers to follow the owner's manual recommendations for their vehicle's fuel."  The findings are based on the results of AAA tests conducted on vehicles using regular (87 octane) and premium (93 octane) gasoline. AAA analyzed vehicle performance, fuel economy and emissions and found there is no benefit to filling up with premium gasoline if your car only requires regular fuel.  RELATED: What your old cars are worth now:  what your old car is worth now  what your old car is worth now  1991 BMW M3 Asking Price: $130,000  "Premium gasoline is specifically formulated to be compatible with specific types of engine designs, and most vehicles cannot take advantage of the higher octane rating," says Megan McKernan, manager of the Automobile Club of Southern California's Automotive Research Center, which partnered with AAA to conduct the research.  Here are some other highlights from the AAA study:  If your car doesn't require premium fuel, but you want to spend a little more money on gas, AAA recommends bypassing higher-octane fuel (premium) and instead filling up with Top Tier gasoline.  What kind of gas do you use in your vehicle? Share your comments below or on our Facebook page.  More from MoneyTalksNews: Car Shopping Online: 5 Keys to a New Car at a Great Price The 35 Two-Year Colleges That Produce the Highest Earners Need a Car Loan ? Here's How to Get the Best Deal
Premium gas can be a waste of money, depending on what type of vehicle you're driving. Read this before your next trip to fill up.