By Sarah Wolpow
PSST!!! I know where you can buy gas for $1.25 per gallon less than what you’re currently paying.
Interested? Here are directions to my secret gas station: head to your nearest highway on-ramp, accelerate gently, set your cruise control to the speed limit and, ta-da, you’re there.
You may have heard that driving aggressively uses more gas than driving calmly. However, you probably don’t think it makes all that much difference. And, if you’re already a calm driver, you probably don’t think that driving yet more calmly could noticeably decrease your gas usage. Think again.
Over the course of a few recent road-trips, I conducted a little experiment. Our car has a display that shows our average miles per gallon (mpg). I made the drives in segments with the cruise control set at 55, 65, and 70 miles per hour (mph), and recorded my fuel economy for each segment. To control for hilliness, I drove the same sections at the same speeds on return trips.
While I expected some differences in fuel efficiency, the results amazed me. I used 25 percent more fuel when driving 65 mph than when driving 55 mp
h, and 10 percent more fuel driving 70 mph than when driving 65.
The U.S. Department of Energy’s website (www.fueleconomy.gov) reports that driving the speed limit can save up to 23 percent on gas usage. Driving deliberately, without rapid acceleration and hard breaking, increased the possible fuel savings to a whopping 33 percent – the equivalent of spending $1.25 less per gallon.
Another interesting website (www.edmonds.com) posts driving test results using a variety of gas-saving tips. Their findings confirmed that slightly increasing (by just a few seconds) the time it takes to accelerate from 0 to 60 mph, and braking gently can improve fuel economy by 25 to 35 percent.
Interestingly, 65 mph is too fast to maximize fuel efficiency. For most cars, efficiency is highest at a “sweet spot” somewhere between 40 and 60 mph. Larger, heavier cars have lower sweet spots than smaller, lighter cars. Even my relatively small car performed much better at 55 mph than 65 mph.
Now hold on, you say. Doesn’t it take longer to get places when you’re driving slower? It turns out that unless you’re going on a very long trip, or speeding outrageously, you will, – amazingly enough – get where you want to go in about the same amount of time. That’s because the Good Green Fairy, seeing your virtuous actions, will zip you to your destination just as fast as the Speed Demon.
Well, no, actually it’s just math. If you drive 70 mph on a half hour highway commute you will get to work just 2 minutes sooner than if you drive 65.
Other than saving money on gas and getting into fewer accidents, why should you care about your driving habits? In a nutshell, transportation, mostly from personal vehicles, is responsible for one third of all climate-changing greenhouse gasses produced by individuals in the U.S. If that doesn’t impress you, transportation also accounts for 51 percent of toxic air pollution and 23 percent of toxic water pollution, according to the Union of Concerned Scientists. No other single thing we do as individuals causes as much harm.
So if you’re looking for one simple behavioral change you can make which will have the biggest benefit for the environment, you’ve found it: take your foot off the pedal.
There is no other action that is available to so many people, saves money, is so easy, and has this large an impact. Overnight, we could take a 10, 20, or 30 percent bite out of our gas consumption without involving anything truly unpleasant or expensive – like carpooling with the grumpy guy next door or buying a hybrid. It’s breathtaking.
A final reason to care about your driving style comes directly from the government’s fuel economy web site: “Strengthen National Security.” If using less oil helps prevent international conflicts – and there are many reasons why it might – can you think of a more splendid patriotic act than this: put a flag on your aerial, get a “Support our Troops” bumper sticker, lobby your legislators for 55 mph speed limits, and drive like your grandma.
Sarah Wolpow writes a regular environmental column for the mid-coast Maine Times Record newspaper and blogs at http://swolpow.wordpress.com.