My Dirty Car Has a Dirty Secret: It's a Surprising Gas Guzzler

CAROLINE DELBERT IS A WRITER, AVID READER, AND CONTRIBUTING EDITOR AT POPMECH. SHE'S AN ENTHUSIAST OF JUST ABOUT EVERYTHING HER FAVORITE TOPICS INCLUDE NUCLEAR ENERGY COSMOLOGY, THE MATH OF EVERYDAY THINGS, AND THE PHILOSOPHY OF IT ALL

- CAROLINE DELBERT

My car's exterior seems to always be dusted with dirt and other gross gunk, which makes me wishfully wonder: Could there be an aerodynamic upside to all that debris?

Years ago, the MythBusters team examined whether a dirty car got better gas mileage as the result of a possible golf ball-like "dimpling” effect.Usin g the same vehicle for consistent results, their dirty car got 24 mpg, while the clean version made it to 26.4 mpg.

Let's say the average person drives 10,000 miles per year. Using the MythBusters results, the driver of the dirty car will use 417 gallons of gas per year, while the driver of the clean car will use 379. That's a not-insignificant difference of 38 gallons per year. The national average gas price is $4.10 as of press time, according to the U.S. Energy Information Administration, which means the driver of the clean car saves $155.80 per year.