While there are plenty of ways we can easily and conveniently go about increasing your car’s gas mileage – i.e. making sure your tires are properly inflated, changing out dirty air filters, etc. – there are also many ways we try to save gas that ultimately end up being a huge inconvenience.
Don’t get me wrong, for most of us reducing the amount of gasoline that we use will require some form of sacrifice. That being said, if you can find convenient ways to save just as much gas (if not more) why put yourself out?!?
Here are the most inconvenient ways for you to try and save gas:
- Driving with the windows up and the AC off on a hot summer day. Because driving with either the windows down or the AC on will reduce your car’s gas mileage, many people will forgo both and roll up the windows and crank up the vent. While this might help you get better gas mileage, it also leads to lots of armpit and back sweat.
- Driving the speed limit. Yes, I realize it’s the law to drive the speed limit, and it’s also a great way to get better gas mileage out of your car, but let’s be honest, most of us have become accustomed to driving at least five to ten miles per hour above the posted speed limit. Not to mention the fact that we’ve become dependent on the extra couple of minutes we buy by going faster than what we should.
- Reducing the amount of time your car sits in idle. Whether it’s adjusting your commuting time so that you aren’t stuck in bumper to bumper traffic, avoiding the drive-thru, or even turning your car off at long lights, reducing the amount of time you sit in idle will greatly increase your car’s gas mileage. Unfortunately, this will probably mean longer walks, increased stress on your car’s starter, alternator and battery and possibly significant changes in your everyday routine.
- Using mass transportation. For many of us who live in the suburbs or in rural areas, mass transportation isn’t an option. And even for those of us who have mass transportation at our disposal, it typically means giving up the convenience of being able to come and go as we please for the sake of following a schedule, which in many cases isn’t on time.
- Buying a more fuel efficient vehicle. For as much as people talk about buying more fuel efficient vehicles in order to reduce the amount of money you have to pay at the pump, for many of us this just isn’t an option. Whether we’re locked into a lease that’s tough to break or we just can’t afford to buy a new car, whatever the reason, it’s pretty tough to try and fix the high gas price problem by buying a new car.
Like I said earlier, saving gas will certainly require a small amount of sacrifice on your part. That being said, I might wait until gas prices hits $4 or $5 to implement some of the ideas listed above.
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I am throughly disappointed in your website. I work for a not-for-profit environmental group in Canada running a program which educates people on how to drive their current vehicles for the most optimal fuel efficiency. The tips you listed and then shot down ARE the best ways to reduce your fuel economy. While leaving your windows up is rather obsurd on a hot day, driving the speed limit is better for you fuel and by speeding over the limit by 10km/h you actually only end up saving on average 2 minutes! Are 2 mins really worth a huge ticket, points off your drivers license and money out of your pocket for more gas? And actually turning of your car during long lights or in drive thru’s does NOT hurt your cars alternator, or battery or anything. It is actually MORE detrimental to leave you car running in idle. Cars were desgined to be turned on and off.
I’m saddened that you decided to publish such a down beat article, and maybe it is because of our greedy over consumptive non-sacrificing lifestyles that the earth is in the state it is, and maybe if everyone learned a little humility modesty and sacrifice we would be a more grateful healthier happier population and earth.
Couple of notes here;
Going faster really isn’t going save you that much time. If you’re on a 100km trip and you’re driving at a 150km/hr you’ll only get to your destination 15 minutes sooner than if you drove at 100km/hr. You will, however, use 150% more fuel – that’s more fuel than it would take you to get there and back again.
Also, about the alternator and starter… the decrease in lifetime of these components and the respective replacement cost is actually significantly less than the amount of money you’d be wasting by leaving your engine running. That’s not to mention that idling causes damage to your engine and exhaust.
Lise – sorry to hear about your disappointment. Maybe if you read the other 300 or so articles on the site you wouldn’t feel so badly.
gnoble – I’m actually a really big fan of turning off my car at long stop lights. I started doing that recently and have seen my gas mileage jump about 8%.
Brian,
I have spent the better part of my day reading the rest of your site, and you do have many GREAT articles, tips and links.
This is a great format and wonderful for people to voice helpful hints, tips, other facts on similar topics etc etc.
I do admit my preemptiveness in commenting on that article. However I have to ask why amoungst all your wonderful up lifting hopeful helpful articles would you publish something which feeds into the negative mindset of those who claim that environmental anything is just a bunch of shinanigans only to be saved for tree-hugging granola hippie freaks (or I’ve so commonly seen written)
i do apologize for my jump on your article and I do enjoy what you’ve got going on here, however this is just the skunk in your beautiful rose patch.
Lise – no worries, and I apolgize for my smart-ass reply back to you.
I guess the undertone of the article was meant to be kind of sarcastic; I think that many of these things really aren’t a great inconvenience in the grand scheme of things, however, we tend to make a bigger deal out of them than what we really should.
I suppose I didn’t lay on the sarcasm as thickly as I had intended.
I have extensively experimented with, documented the effects of, and calculated the individual and societal effects of all of these. For example, in the car in which I originally started my experimentation in 2005, a Jeep Grand Cherokee Limited, I raised my average mileage from 14.9 m.p.g. to over 23 m.p.g. I used all the techniques in your blog and more, again, extensively documented in my blog at http://hamiltonianfunction.blogspot.com/.
I calculated here (purely using estimations): http://hamiltonianfunction.blogspot.com/2006/04/ween-us-from-imported-oil-maybe-not.html that elimination of drive through windows would save the U.S. about 350,000 barrels of oil per year, or about 0.007% of our imports. But I stopped using them despite this very small number.
The time factor is not insignificant. See http://hamiltonianfunction.blogspot.com/2006/04/use-of-time.html for some numbers.
Haha, this is funny, we (lise and i) actually work together! Although I guess work is a bit subjective if we can afford to spend all this time posting!
I thought that something was up with your ‘longer walks’ comment. But you do bring up some good points though, a lot people would find these changes huge inconvenience on their lifestyle. In truth people never drive the speed limit, crank up the A/C whenever possible, hate taking the bus and don’t have the money for new fuel efficient cars (w/o sacrificing size). If it weren’t the fact that gas prices have doubled in the past six years, it would be even harder to convince people to make these changes!
Hmm.. to gnoble,
I have to question your figures, considering that going 100 kilometers at 100 kilometers per hour takes an hour, going the same distance at 150 kilometers per hour takes 40 minutes. I’m thinking that’s a savings of 20 minutes, which makes sense – going 50% faster should reduce your time by 33% (I majored in mathematics).
I’m not sure that you would use 150% more fuel. That would be a reduction in m.p.g. of 60% (the same as an increase in liters per kilometer of 150%). No figures I have determined from my experience or calculation indicate a decrease of that magnitude in fuel economy, even for a vehicle with very poor aerodynamics (the type that would be most affected).
Nothing personal, but when such fundamental errors are made, it calls into question the accuracy of your other points as well.
Hmm, yeah I’m not a math major by any facet of the imagination, but one of my co-workers got a doctor of physics to do some math for us. This is what he figured out (It’s actually 125% more fuel, my mistake):
Why do I burn more fuel the faster I go?
Basically, higher speed involves a higher force related to air resistance. As speed goes up, the force required to push a vehicle through air rises significantly.
The power required to overcome the aerodynamic drag is given by:
Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 80 km/h may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 160 km/h requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice faster. Since power is the rate of doing work, four times a work in half the time requires eight times the power.
If the image insertion didn’t work above, you can check out the formula at
http://www.clean.ns.ca/default.asp?id=190&pagesize=1&sfield=content.id&search=179&mn=1.21.52.160
It also has extra information about our program!
Well, let’s take a look. I’m currently driving a Land Rover LR3 with a coefficient of drag (Cd) of 0.41 and a frontal area (A) of 3.15m^2. The aerodynamic drag is (Cd/2)*d*v^2*A where d is fluid density (for air approximately 1.16kg/m^3 and v is velocity (actually speed in this case).
So: at 150km/hour (41.7 m/s) the aerodynamic drag is (0.41/2)*(1.16)*(41.7^2)*(3.15)=1302 N (say 1300 Newtons). The other external force to be overcome by converting the chemical potential energy of gasoline to mechanical energy in the cylinders is tire rolling resistance. At typical highway speeds, as best I can determine, this number is about 0.015 times vehicle weight. I’ll assume it increases linearly with speed and that 150 km/hr is 1.5 times typical highway speed, so I’ll estimate 1.5*1.5=2.25 times vehicle weight. My LR3 typically weighs about 26000 N so this force is something like 585 N so the total external force to be overcome is about 1885 N. Now, force times speed is power, so I need the burning of fossil fuels to give me energy at the rate of 1885 N *41.7 m/s or 78,600 watts. This is equivalent to 105 horsepower. Whew.
The same calculations for the speed of 100 km/hr (27.8 m/s) yield an aerodynamic drag force of 579 N and a rolling resistance of 390 N for a total of 969 N. At 27.8 m/s this requires 26,900 watts or 36 horsepower.
All this is very interesting, but since I’ve assumed that rolling resistance and all manner of dissipative forces in the car (pumping of fluids, driveline friction, etc.) are linear functions of speed as is distance covered per second, the ratio of fuel consumption rates at those two speeds will depend only on aerodynamic drag, which increases as a power function of speed. In my LR3 therefore, I should use )(1300-589)/579)*100%=124.5% more fuel at 150 km/hour. I’m more than willing to call it 125%
. And since the only variable in the aerodynamic drag calculation specific to my vehicle is Cd and it is a linear factor, the same ratio will hold for any vehicle.
So, with your permission, we’ll agree on 125% more fuel (or 225% as much fuel) and a time savings of 20 minutes for a 100 km trip.
This has turned into quite the discussion! I think that Brian’s initial point was that these things do save you money and increase your gas mileage, but they’re just a little more inconvenient than others. I would have to agree that some of these things I don’t plan on doing religiously unless prices are quite a bit higher. I guess I’m willing to pay a little more to keep driving the way I normally drive!
I’m a bit thick so I wonder if someone can answer me this question:
Ok, amazingly, travelling at 150 km/hr uses 125% more fuel than travelling at 100 km/hr. But, you’ll arrive and turn off your engine 20 minutes sooner, so won’t that negate to a certain extent the extra fuel used? I mean, you’re using 100% less fuel for 20 minutes aren’t you?
As I said, I’m not very bright, maybe I’ve got it all wrong… :-O
andy, fuel consumption is rated per km, not per hour. i’ll try to make it clear for you: let’s say you have to drive 100km. going at 100km/h you’ll burn let’s say 10l (10l/100km). Going at 150km/h, you’ll burn fuel at a rate of 22.5l/100km. So for 100km you’ll burn 22.5l of fuel.
The best way to improve your fuel efficiency is to identify the marketing tactics used to convince you that bigger/faster is better, and consciously resist those tactics. Ever see the commercial where the guy tries to beat the semi onto the highway with his truck and the attached trailer? The product “provides more power” so he can accelerate faster. The other option? Wait less than 1 second for the semi to pass and merge on without flooring it, no special product needed.