DEBUNKED: 15 Car Myths That People Still Believe

Most American adults can drive, but that doesn't mean we understand everything about our cars.

And it turns out, much of what we think we know is totally wrong.

For the purposes of education, we've compiled 15 common car myths.

Some are outdated, some are misunderstandings, and one or two are dangerous.

They're all total bunk.

1. Manual transmissions offer better fuel economy than automatics.

This used to be the case, when automatic transmissions were relatively new.

But recent advances in the technology (like the continuously variable transmission, which offers an infinite range of gear ratios) eliminate the advantage of manuals, and in some cases put automatics ahead.

2. You can make your car much more powerful by filling it with jet fuel.

Definitely not - in fact, your gas-powered car won't go anywhere at any speed if you put anything but gas in the tank. Conventional car engines can't combust kerosene.

Last year, a fuel delivery service accidentally delivered kerosene jet fuel to a New Jersey gas station. Some cars were filled with the fuel, and promptly stalled.

3. A bullet to a car's gas tank will lead to a big explosion.

A common trope in action movies is the moment where a well-aimed shot turns a bad guy's getaway car into a flaming wreck.

Discovery's "Mythbusters" proved that in real life, bullets go right through the tank - without fire, there's no ignition, and no explosion.

4. Turning on the air conditioner is better for fuel economy than opening the windows.

This one's harder to pin down. Mythbusters found an SUV with open windows will go farther than one with the A/C on. Consumer Reports looked into it, and found that A/C leads to a "slight decrease in fuel economy," but recommend using it anyway, to keep the driver alert and comfortable.

For the final word, we looked to a 2004 study by GM and SAE. It found that for both sedans and SUVs, at a variety of speeds, turning the A/C on (at medium power) gobbles up more fuel than driving with the windows down.

5. Using your cell phone while pumping gas can trigger an explosion.

I was once scolded by an aunt who was convinced that my checking my email while she filled her gas tank would engulf us both in fire.

The Federal Communications Commission investigated "rumors" that a wireless signal can ignite fuel vapors, and concluded: "there is no documented incident where the use of a wireless phone was found to cause a fire or explosion at a gas station," and "scientific testing, however, has not established a dangerous link between wireless phones and fuel vapors."

6. You get more for your money when you fill your gas tank in the morning.

The logic behind this one is that when temperatures are cool, gasoline is denser, so you get more fuel per gallon pumped.

But, as Consumer Reports explains, gasoline is stored in underground tanks, where the temperature hardly fluctuates. So the gas coming out of the nozzle is basically always at the same density, whenever you decide to pump.

7. Hiding behind a car will protect you from gunfire.

Another common movie move is to hide behind your ride when the bullets start flying. Some bullets may not be powerful enough to cut through the steel, but it's not a safe bet.

As Business Insider reporter and former Marine Geoff Ingersoll has written: "Cars are not cover! They are concealment. This isn't the movies. Bullets go through cars. Quietly find some earth, stone, or steel to hid behind."

8. Off-brand gas will hurt your car.

Actually, there's no good reason to avoid "off-brand" gas stations that charge less. Name-brand stations like Mobil and Shell may put extra engine-cleaning additives in their gasoline, but using generic gas won't harm your engine in any way - it has to meet the same standards as the pricey stuff.

9. Electric cars are more likely to catch fire after a crash than conventional cars.

Stories of Fisker Karmas and Chevy Volts catching on fire have spread, but the truth is that gas-powered cars can ignite too, in the right (or wrong) circumstances.

In 2012, the National Highway Traffic Safety Administration investigated the crash-related fire risk in the Chevy Volt, and concluded: "The NHTSA does not believe that Chevy Volts or other electric vehicles pose a greater risk of fire than gasoline-powered vehicles."

10. The Toyota Prius gets worse gas mileage than a BMW M3.

This one comes from a 2009 episode of "Top Gear," which ran a test in which the powerful BMW actually got more miles per gallon than the little hybrid. But what people forget is that that test was done on a track, with the Prius driving as fast as possible, and the BMW just keeping up.

Yes, the M3 is more efficient than the Prius in very specific conditions. But if you drive on public roads and want to save on fuel, take the hybrid. Host Jeremy Clarkson explained, "It isn't what you drive that matters, it's how you drive it."

11. You need to change your oil every 3,000 miles. Or never change it at all.

That rule may have held for older cars, but it's now a thing of the past. By now, it's been so thoroughly debunked, it has its own Wikipedia page. In turn, that has spawned another myth: You never actually need to change your car's oil.

But while most modern cars can go as far as 10,000 miles without fresh oil, the occasional change is still necessary. Taking on the question, "What if I never changed the oil in my car," How Stuff Works answered: "Eventually, as the oil gets dirtier and dirtier, it will stop lubricating and the engine will quickly wear and fail."

12. A dirty car is more fuel efficient than a clean one.

The thinking here is that mud caked on the side of a car works like dimples on a golf ball, reducing drag. Mythbusters checked this one out, and found that dirt particles actually create more drag - and can reduce fuel economy by a whopping 10%.

13. Premium fuel makes your non-premium car run better.

More expensive gas isn't purer or cleaner than the regular version. It is less combustible, which makes a difference for powerful engines, but has no effect in your Camry.

The Federal Trade Commission puts it simply: "In most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit."

14. Red cars are pulled over for speeding more often than non-red cars.

When it comes to cars most likely to get pulled over, color doesn't make a difference. A study by Quality Planning, published by Forbes, revealed the most ticketed car is the Mercedes-Benz SL Class convertible. That's no surprise, as the 2013 version goes from 0 to 60 mph in 4.4 seconds, according to Edmunds.

15. Circuses use trap doors and other tricks to fit all those clowns in those tiny cars.

We can't guarantee there aren't some frauds out there, but the true clown car doesn't use any slight of hand.

Greg DeSanto, executive director of the International Clown Hall of Fame and Research Center, explained to Car and Driver that the key is taking everything possible out of the car, "then it's a matter of shoving in the clowns."

Consider yourself educated.