What you've been told is a lie! Here's the truth
Your car doesn't just "get what it gets" Its fuel economy varies drastically from one situation to the next. If you know what those situations are, you can save a ton of fuel by maximizing efficient driving and reducing inefficient driving. It's not just about slowing down: merely backing off the gas can actually cost you fuel in some situations, and you won't end up saving that much.Buying a hybrid is not the best way to save fuel. Don't get me wrong. I love hybrids, and they can certainly save you a lot of gas. But changing cars always costs you thousands of dollars, whereas learning to drive efficiently costs little or nothing. Hybrids in particular are very sensitive to driving style, and you're much better off learning to drive efficiently first.
The Big Three
Anticipate speed changes and minimize braking.  |
For local driving this is the most important tip. It also takes the most effort and concentration to learn and practice consistently.
Around town, most of your fuel is burned in the repeated effort to get your vehicle's speed up, over and over again. Braking throws it all away and makes you start over. Saving fuel in town is all about reducing your speed changes, and especially the amount of momentum you burn off with your brakes.
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Slow down! But keep 'er steady |
Speeding costs you more in fuel than it saves you in time. At highway speeds, a 10 mph increase in speed costs you 25% more fuel.
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| Be Consistent | Especially with the anticipatory driving techniques above, people invariably tell me, "Oh, I'm already doing those things." O Rly? If you're not getting at least the EPA city rating in town, then no you aren't. You need to do this stuff all the time, not just occasionally and patting yourself on the back for remembering to do it once in a while. Try harder and keep at it. |
Other important techniques
The Big Three above matter most, but here some other important things to do.
Air up! |
The tire pressure indicated on your car's door jamb is recommended by the automaker for comfort and is minimum, not a maximum. The maximum pressure (usually 44psi) is stamped on your tire sidewall.
Inflating your tires to this pressure when cold is not overinflation, will not cause premature wear, actually reduces your risk of blowouts, and will save you 5-10% on the highway. There is an enormous safety margin built into this pressure rating, and your tires are designed to be run under a full load at this pressure! |
Avoid idling. |
Idling wastes anywhere from 1/2 ounce to 2 ounces per minute, and those figures can double with the A/C on. Ounces quickly add up to gallons. Never let your car idle while parked, never idle your car to "warm it up," and kill the engine while stopped at longer lights. The idea that restarting an engine takes a lot of fuel is a myth left over from the days of carburetion. Restarting today's engines takes less fuel than idling for 10-15 seconds, and won't hurt your starter. When in doubt, kill it!
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Limit A/C use. |
Sometimes you just need A/C, but it does increase your fuel consumption quite a bit. Get along without whenever you can stand to. Use a sunshade or park facing north on sunny days. When the A/C is on blast it, then kill it when you don't need it.
At highway speeds, though, use the A/C rather than driving with the windows down. |
Pulse and Glide. |
Once you've mastered the above, this is the big one. It might seem counterintuitive at first, but engines are most efficient under a moderate load. Believe it or not, steady speeds present a very light load to today's overpowered engines -- even on the highway. If traffic permits you to vary your speed by 5 or 10 mph, you can save large amounts of fuel by alternately "pulsing" at a moderate rate and then coasting. If you do it right, you may find yourself spending more time coasting than pulsing! It can take a while to find the sweet spot -- usually 20-40% of the engine's power -- but on a smaller car this alone save you 10 mpg. |
Monitor your fuel economy. |
To get the feedback you need to improve your mpg, you need a resettable trip mileage display. Most people get an immediate 10-20% jump in mileage simply because you can see the results of your techniques as you practice them. Any car built since 1996 has a diagnostic port under the dash into which you can plug a device like the ScanGauge II. Consider getting one. It will cost you $160 but will pay for itself in the first year. |
How Not to Do it
You can achieve all the fuel savings I'm talking about without using any of the below dangerous and/or controversial techniques!NO truck drafting |
I do not draft trucks, and I do not recommend it. Never drive next to a truck or follow closer than 2 seconds. It's not worth the risk. Don't think a big SUV or pickup with "more metal around you" will make this safe, either. A loaded semi weighs 80,000 pounds and will squash your F-250 like a bug. Stay away.
I repeat: NO CLOSE-IN DRAFTING! Always leave a buffer of at least 2 seconds in front of you. 3 to 4 seconds is better. | ||||
NO extreme cornering |
It's not worth it to go racing around corners at the expense of safety.
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NO ignoring pedestrians
| Our roads can be a pretty unfriendly place if you aren't in a car. Let's all do our part to make it easier. It just might get us out of our cars more. That's good for both our economy and our health. Even a hypermiler can afford the tiny extra amount of fuel.
| Engine-off gliding?? |
It's not as dangerous as people think if you know what you're doing. But the savings are small and there is no need to do it!
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Aero modifications?? |
 Things like smoother hubcaps and smaller mirrors can easily save a percent or two. Underbelly pans and wheel skirts may save yet more, and extreme measures like big air dams and boattails can yield big fuel savings on the highway. But unless you're an adventurous DIYer, don't bother.
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Equipment Choices
Techique matters most, but equipment choice makes a difference too.Buy Low Rolling Resistance tires. |
This could cost you nothing if you do it when you're buying new tires anyway. Consumer Reports tests tires for rolling resistance. Many Michelin models roll well and are clearly identified as such on their website, and the better Toyo touring radials offered at Northwest Les Schwab stores are also quite efficient.
Also, it is a popular but false myth that traction comes at the expense of rolling resistance. Michelin, Dunlop and Nokian all make excellent winter tires that grip fantastically well on snow and ice, yet boast low rolling resistance. |
Savings: Medium. Cost: from free to $500. Difficulty: Easy. |
Clear the roof. |
Even a bare rack without accessories costs 1-2 mpg on a midsize car. Add a couple of bikes or cargo box, and the damage jumps up to 4-5 mpg. Trunk/hatch or hitch mounted racks can carry bikes, skis and even cargo, and have a minimal impact on fuel economy. | |
Buy a more fuel efficient car. |
Hybrids and diesels are great -- as are less expensive economy cars -- but it's more cost effective to learn to adopt the above techniques and drive for fuel economy first. Then you'll get really good mileage when you later trade in for a more efficient car.
Some of my favorite fuel efficient vehicle choices are listed on my Cars web page. |
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Drive a stickshift. |
If you're already buying a car (see the previous tip), get a manual transmission unless you're buying a hybrid or your physical condition prevents it. If you can master the above techniques you can certainly learn to drive a stick. They are more efficient than automatics, and allow much more effective use of the techniques I've described above. Even though many manuals are geared lower than automatics, thanks to the additional control you get with a stick you're still likely to get better mileage. |
My mpg
My Current mpg
Since early 2008 I've been driving a (gas-powered) VW Jetta Wagon rated at 22/29 mpg under the current EPA methodology. I record my fuel usage at cleanmpg.com. Here's how I'm doing so far. After the first couple months of getting used to the car, I have not had a tank below 29 mpg except for a 26 mpg tank in December 2008 when we had 13" of snow and I spent a week driving on unplowed streets. Even with our now ethanol-laced fuel, I've had a number of tanks in the 34-35 mpg range, have been getting over 30 mpg even in town in the winter, and have even beat 40 mpg on the highway.
My Initial Results
Following are my Subaru's overall average from May 2007 through January 2008, and a graph of fuel economy versus daily high temperature over time. Note how mpg improves in the warmer months and goes down in the cooler months.
Prior to starting this exercise, I had consistently gotten mileage in the low 20s in the city and low to mid 20s on the highway on all 3 of my Subarus. In 2006 I made a conscious effort to drive less enthusiastically around town, but this only netted me a gain of 1-2 mpg. Even after the change I got about 21-22 in town in winter, 23-24 in town in summer, and 23-26 on the highway. The highway mpg was so poor due to high speeds (all too frequently in the mid 70s) and the presence of a roof rack frequently laden with a cargo box and/or bicycles.
Then in the spring of 2007 I started reading up on "hypermiling" and various techniques used to improve fuel economy. Up to that point I had assumed the 1-2mpg improvement from easing up on the gas was about all I could get. I never imagined I could see the 30% improvement I had achieved since I got serious about it that May. Even in winter I was able to average over 28 mpg, and in summer well over 30 mpg. On a long roadtrip I even achieved a achieved a 500 mile tank and 35 mpg.
Links
- cleanmpg.com, founded by Wayne Gerdes (the godfather of Hypermiling), is a wealth of information on driving for fuel economy. If you have additional questions about the techniques I've described, register for the forums on this website and ask away, and it's one of the nicest groups of people on any Internet forum.
- cars.html on this website describes the fuel efficient vehicles that I recommend.
- fueleconomy.gov is the source for specific fuel economy ratings of vehicles going back to 1985.
- edmunds.com is the best place for general reseach on cars going back to 1990, and has a Green Car Guide full of excellent articles related fo fuel economy.
- gassavers.org is another good source of fuel economy information.
- Numerous sites for specific fuel efficient cars, such as priuschat.com, tdiclub.com, fitfreak.net, metrompg.com, yarisworld.com and insightcentral.net have active discussion boards related to fuel economy. Go in with a thick skin though, because many of these forums have a lot of inexperienced, aggressive drivers who may be hostile to your ideas.
- The Tufts Climate Initiative issued ratings of carbon offset companies in 2007. Native Energy and Atmosfair are among the recommended choices.