The Checkout

True or False, These Tips Save Gas?

We've all heard the tips on how to save gas. And, as fuel prices continue to climb, we're hearing them almost daily on TV and radio: Don't drive aggressively. Drive at lower speeds. Use cruise control. Don't use air conditioning. Keep your tires properly inflated. Avoid excessive idling.

So, which ones are true? Edmunds.com, a popular online Web site that has all sorts of car-buying and maintenance advice, put the tips to a test (many tests actually) to see if they can really, truly help you save gasoline.

Some results may surprise you. For instance, tire pressure had no measurable effect on gas mileage in Edmunds' tests. Similarly, there was no measurable difference in using air conditioning or driving with it off with the windows open. "So just do what's comfortable," Edmunds says. (Meanwhile Heather L. Cooper, an assistant professor of mechanical engineering in Purdue's College of Technology said if you use A/C, do it on the recirculation setting to minimize the energy required to maintain a constant temperature.)

But some of the other tips do indeed help you trim your fuel bill. For example, Edmunds found that by easing up on the gas pedal when accelerating, you can save an average 31 percent on gas. So, instead of going from 0-to-60 in 10 seconds, try doing it in 15 seconds. "You'll feel the savings immediately."

Similarly, on long trips, slowing down to the speed limit can result in an average fuel savings of 12 percent. Of course, Edmunds notes, driving the speed limit does have its drawback: "Impatient drivers behind you." In their test, "one driver became so irate that he tried to run our editor off the road."

Visit Edmunds.com for complete test results.

By  |  April 27, 2006; 6:30 AM ET Consumer Tips
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Comments

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"Impatient drivers behind you." In their test, "one driver became so irate that he tried to run our editor off the road."

Just don't do it in the left lane. Stay to the right.

Posted by: Anonymous | April 27, 2006 7:09 AM

Accelerating moderately will save gas for YOU but not necessarily for all drivers as a group. However, around here if you are at a light and move leisurely away from the light, far fewer cars will be able to get through the light before it turns red again. The savings from slow acceleration will probably be overwhelmed by the losses from all the extra time spend idling at lights.

Suppose 20 cars can get through a light if everyone accelerates at a reasonable rate. If everyone accelerates at a much slower rate probably only 15 will get through. If 20 cars were arriving for each light cycle after 10 cycles there will be 50 cars waiting for the light each burning fuel while they wait through 3 cycles of the light.

Conclusion: When traffic is light, a light touch on the pedal is probably a way to save gas. When traffic is heavy a heavier foot is probably best to lower total gas used.

Posted by: Arthur Grube | April 27, 2006 8:47 AM

Very odd results.... I've owned three different cars and noticed big differences when my tires are at correct psi vs when they're low, and when using A/C in the city. A/C on the highway doesn't seem to matter at all, though.

Posted by: Mike Sellery | April 27, 2006 9:11 AM

I tried my own little experiment driving the way I usually do for one week, and another week by following some of the tips (eg. drive at the speed limit, slow acceleration), but I found no noticable difference in gas mileage (it was actually 1 mpg less by following these tips).

There is probably much greater effect on gas mileage based on how much you sit idling at red lights and getting stuck in traffic.

Posted by: Will | April 27, 2006 9:32 AM

Sticking with the old 55 MPH Speed Limit would have saved both gas, and lives.

(And, of course, more gas means more pollution.)

Posted by: John Johnson | April 27, 2006 9:33 AM

Dunno if my decision to go with stick shift is wise now!!! In city traffic, I can control on the gear in which am on - example I can stay on 4th gear even on 20 mph...from 45 to 25 mph I dont change gears from 5th!!

Posted by: Anonymous | April 27, 2006 9:54 AM

The problem with this article is that it sounds like they only tested the tips for a long highway-speed trip. Some of the "no difference" results might not apply to urban driving. For example, wind resistance from an open window may not be a factor at low speeds in the city, but does at high speeds, causing the engine to work more and negating the AC savings.

Posted by: tallbear | April 27, 2006 1:22 PM

One simple answer, but only one, is DriveSmartAmerica! Legislation that mandates a fuel economy gauge (MPG) in prominent view on each new car and truck sold in this country would provide drivers with feedback they could use to moderate driving habits by slowing down and avoiding jack-rabbit starts, thus saving both gas and lives. Visit my website at http://groups.yahoo.com/group/Drive-Smart-America/ for further detail.

Posted by: Peter Gadzinski | April 27, 2006 1:45 PM

I suspect the AC usage might also be tested in a large vehicle with a large engine. My little car feels like it's getting smacked in the nose every time the AC kicks in. Also, 5-speeds almost always have the potential for being more fuel-efficient. They use less fuel at idle, and choosing the right gear for accellerating (or cruising uphill) lets you keep the engine running at the right RPM.

Posted by: KevinR | April 27, 2006 2:22 PM

For the comment on irrate drivers behind you, people need to pay attention to all the cars around, not just the car to the front and to the side(s). I love the people who tell me to speed up when really it's the three cars infront of me going slow. I can't go faster than the car infront of me and I can't move over when there is an 18 wheeler next to me. Be aware people, be aware.

As for higher gas prices, they're just going to get higher and talking about them day and night is not going to bring them down. So let's talk about something different on the radio and television.

Posted by: Duke | April 27, 2006 2:24 PM

Why do we never talk about carpooling? I'm going to work with two other people and we're having a great time!

Posted by: Mark S. | April 27, 2006 2:37 PM

Really....the best way to keep gas usage down is tobe smart about your travel. Don't drive past the gocery on your way home to change clothes to go back to the grocery. Combine errands and plan your route. Granted, this dosen't help the DC commuting trafic, but it will help.

Posted by: Duke | April 27, 2006 2:40 PM

Want to do something about the "irate" drivers behind you, who are constantly pushing you to go faster, and engaging in CRIMINAL behavior like trying to run you off the road?

Go to www.crashprevention.org and become a member today.

Enough is enough!!

Posted by: Lisa | April 27, 2006 2:52 PM

"(Meanwhile Heather L. Cooper, an assistant professor of mechanical engineering in Purdue's College of Technology said if you use A/C, do it on the recirculation setting to minimize the energy required to maintain a constant temperature.)"
I don't think this lady is getting the full professorship anytime soon. A compressor, which increases fuel consumption by taking energy from the engine, only has two settings- on and off. An MVAC (motor vehicle A/C) does not work like a home A/C, where it shuts off when you reach a certain temperature. It's always either fully on or off. If it's two cold and you turn the dial to a little less cold, all that does is mix warmer air in with the cold air- it doesn't lessen the compressor cycling rate or anything (although they are trying to develop variable compressors that do do that).
Incidentally, recirculating the air can cause moisture to accumulate in your A/C, leading to a permanent mildewy smell.

Posted by: doodoobrown | April 27, 2006 3:07 PM

Unless somehow we can harness the hot air coming from Wasington, the only solution is to reintroduce real horse power.

And - Whoa, Nelly! - don't be too late getting into oat futures.

Posted by: Clay Bullröhr | April 27, 2006 3:37 PM

$3 and $4 per gallon gas will give people an incentive to ditch their monster SUV's (Stupid Useless Vehicles).

The high price of gas hurts because too many Americans live wasteful lifestyles and refuse to adjust. They'd rather whine about oil company profits than take a hard look at the Ford Excursion in their driveway.

Europe and Japan have learned to live with $3-4 a gallon gas and we'd better learn to as well.

Posted by: Ken L | April 27, 2006 7:39 PM

Hey, John Johnson, let's all go 0 MPH and save even more gas and even more lives!

And Ken L, why on Earth would you care if Americans "refuse to adjust?" What business is it of yours? Just tune out the whining about oil company profits (which whining, of course, will only bring about legislative action which will make things worse).

Posted by: Guzzler | April 27, 2006 8:25 PM

55 may save some gas mileage but it does not save lives. Fatalities decreased when speed limits were increased. Overall, people just to be aware of other drivers and drive assertively (IE.. move to the right, merge appropriately (accelerate, not stop!), maintain proper speed WITH traffic. The funniest, yet infuriating traffic story I ever saw was Sam Donaldson on primetime live riding in a van doing 50 in the left lane on 495. Of course people were ticketed off! Move left Sam! Then under the "supervision" of the police, they increased their speed to 65. Are they joking? Anyway, Speeding tickets are a disguised tax not a safety tool. Not being aware causes fatal accidents, not a reasonable speed (= ~75mph, what the highways are engineered for). I understand traffic accidents can be deadly...yet people focus more on slowing down then actually educating people on how to drive intelligently. More education = better drivers = less road rage. How laughable is an anti-road rage campaign... it's called move right, not ticket the person peeved cause some idiot is talking on their cell phone in the left lane doing 50.

Posted by: Doc Johnson | April 28, 2006 8:17 AM

Discovery Channel's MythBusters did an episode on gas milegae with the AC on and off, finding no discernable difference.

Posted by: Lester Burnham | April 28, 2006 11:01 AM

My Passat users manual explicitly cautions against long use of recirculation mode; not only is moisture build-up a problem, but CO2 build-up from passengers as well as outgassed material from plastic in the vehicle is the potential problem. It may be that VWs are better sealed than other cars (that seemed to be true of the 60's Beatle), but i would imagine the prudent thing in general is to only recirculate to avoid a passing hazard, such as a visibly polluting diesel.

Posted by: matt h | April 28, 2006 11:32 AM

State Highway should use the electronic highway signs less. People slow down to read them (sometimes only 5 words) which causes traffic backups. For the last week, the signs have read "Slow Down/Save Gas."

Posted by: ProfessorB | April 30, 2006 7:25 AM

To Mr. Johnson, let me quote you:

"Sticking with the old 55 MPH Speed Limit would have saved both gas, and lives."

As appealing as that sounds, this is not backed up by facts or statistics.

In fact, traffic deaths and death rates have been falling for a significant amount of time regardless of speed. This flies in the face of what seems to be common sense, but then, most people have little understanding of how and why traffic accidents occur.

As to saving gas, the difference between 55 mph and 65 mph pales in comparison to the simpler idea that we'd save a lot more gas if SUV's weren't exempt from CAFE.

I realize there are some people on the road who would rather drive an SUV at 10MPH than make meaningful changes, but that's no way to build a comprehensive transportation policy.

Posted by: Oh Brother | May 2, 2006 3:24 PM

I want an electric car with solar panels on top. We can do it on Mars why not here on earth?

Posted by: John Pike | May 3, 2006 10:11 AM

Low tire pressures cost gas mileage. I monitor consumption carefully and see at least a 1 mpg difference if my tires are low. I've verified this more times than I can count. Just because a statement appears on a web site, doesn't mean it's true. I also get a fraction more than 30 mpg from my BMW while most drivers claim only 22 - 24 mpg. The difference is careful driving and braking, and not treating every stop light like a drag strip start. People are clueless. There are so many ways to conserve gas, and all they do is complain.

Posted by: vfr-rider | May 4, 2006 12:09 PM

I'd say that myth busters episode you were watching did find a difference w/ A/C v. windows down when driving at highway speeds. Identical SUVs both drove around a track w/ cruise control, one w/ windows down and one w/ A/C on max. The windows down ran out of gas first. Plus the people in the A/C car were freezing despite wearing coats, meaning a normal person would use even less a/c. I'd say there's a difference at highway speeds.

Posted by: wha? | May 5, 2006 4:14 PM

You can pay $1.00 for one gallon of gas; cash or use any credit card ..

Just do three things: (1) Ask your local media to write an article inform new immigrants 'that they don't need to warm up car engine' (now they are running 35 million engines for about 10 minutes every morning). They don't know that in U.S. the 'pressurized oil pump' was invented 20 years ago, making warming up unnecessary. Stopping warming up these cars would reduce gas prices 75 cents per gallon. (2) Join the 'BGB CO-OP' (Buying Gas in Bulk). The members of such CO-OP in Minnesota are now paying (as of 09/04/05) 98 cents/gallon. (3) Request ZERO HOUR GUIDE describing the solid fuel (zero pollution ethanol pellets), further reducing costs; the final price can be 40 cents/gallon. How to organize the CO-OP in your city? Please send email to Edward Romanoff uschapter@yahoo.com

Posted by: Edward Romanoff | May 10, 2006 5:46 PM

First of all, I don't know anybody who drives like this! (see the actual test below). Secondly, My wife and I drive nearly Identical 96 Mark VIIIs. I drive agressively - she drive moderately. The difference in overall fuel milage is less than one percent!!!

"Test #1: Aggressive vs. Moderate Driving

This is gonna hurt. Our tests showed that the most significant way to save gas is: you. And we're talking massive fuel economy gains. Think you need a hybrid? Chances are you've got hybrid-style mileage in your gas pedal foot. Don't mash the gas when you start up. Take the long view of the road and brake easy. This tip alone can save you unbelievable amounts of gas. If you slowed your 0-to-60-mph acceleration time down from your current 10 seconds to a more normal city pace of 15 seconds, you'll feel the savings immediately.

Method: We conducted this test four times. The first time we did the full 55-mile loop once by accelerating aggressively 15 times at 3/4-throttle from zero to a cruising speed of 75 mph. We also applied the brakes hard to come to a full stop. Then, we drove the second loop by accelerating moderately 15 times at 1/4-throttle to a cruising speed of 70 mph. We braked lightly to a full stop. In the second set of tests we drove 25 miles making 25 rapid accelerations to 65 mph at 3/4-throttle. After 1 minute of cruising we braked hard and repeated the cycle up to 65 mph. We then drove the same distance making 25 moderation accelerations to 60 mph at 1/4-throttle. After 1 minute of cruising we applied the brakes easily and came to a full stop."

Posted by: Anonymous | May 11, 2006 1:39 PM

Correction:

"minimally process" should be

"minimally processed"

Posted by: Nancy Garrett | May 11, 2006 1:53 PM

Every morning, there are 6-7 cars/trucks idling for 5 to 15 minutes while the owners are getting ready to go to work and have breakfast. Meanwhile, the neighborhood is thick with fumes from exhaust . I fail to see the rationale for idling . Can you please explain it to me?

Posted by: Tania Calhoun | May 27, 2006 6:24 PM

Cruise control has been cited as one way to save gas on longer trips. My guess is that very few people have actually tested the validity of this claim. This claim is plausible when driving on roads that are more or less level and have only slight grades. In areas where the terrain is highly variable, cruise control will actually increase fuel consumption. Why? First understand that cruise control is designed to do one thing: maintain speed at whatever the cost. When CC is confronted by a challenging grade, it kicks to a high-revving, fuel guzzling lower gear. To save fuel let your car slow naturally while climbing, then let it safely speed up when going downhill. 45 years of driving and comparing shows this method can give an improvement of 1 to 1.5 mpg on a trip where variable terrain is characteristic. When this is added to proper tire inflation, moderate AC use, fewer round-the-block trips, a gentle pedal, slightly slower freeway driving, and other prudent driving habits, the money savings can be downright exhilarating--even habit-forming.

Posted by: Jim Harr | July 7, 2006 6:55 PM

this will definately save you some gas (not to mention $$$)
http://www.candy4gas.com

Posted by: Anonymous | October 3, 2006 10:11 PM

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