Fuel Economy: The MPG illusion
December 15, 2008 6:40 PM   Subscribe

Fuel Economy: The MPG illusion. Quick, which of the following reduces gas consumption more? a) trading in a 33 mpg car for a fuel-sipping 50-mpg car b) trading in a 14 mpg SUV for a 16-mpg SUV hybrid. Answer: They are both roughly the same. This not surprising once you apply a little math. "Miles per gallon is a ratio. Gas consumed is an inverse of that ratio. A ratio and its inverse do not have a linear relationship. They have a curvilinear one."
posted by storybored (108 comments total) 2 users marked this as a favorite
 
c) trading in a 14 mpg SUV for a fuel-sipping 50-mpg car
posted by brain_drain at 6:46 PM on December 15, 2008 [32 favorites]


Yeah. That's not an illusion, that's a false dichotomy.
posted by specialfriend at 6:48 PM on December 15, 2008 [31 favorites]


What's up with gas prices?
posted by qvantamon at 6:49 PM on December 15, 2008 [19 favorites]


You don't even need that much math to figure that out.
posted by fshgrl at 6:52 PM on December 15, 2008


d) bus pass
posted by fleetmouse at 6:53 PM on December 15, 2008 [22 favorites]


Option A reduces gas consuption by about 50%, and option B does so by about 14%.

(Granted, the absolute changes aren't so stark, but then you've got to cop to the fact that while the delta may be small, the guy with the 33 mpg car is already using about half as much gas as the guy with the 16mpg SUV. And then there's option c, going from the 14mpg SUV to the 50 mpg car.)

On the other hand, going from a 1 mpg car to a 3 mpg car is, in both absolute and percentage changes, a huge win!!!!
posted by kenko at 6:55 PM on December 15, 2008 [4 favorites]


On the other hand, going from a 1 mpg car to a 3 mpg car is, in both absolute and percentage changes, a huge win!!!!

Going from a 1 mpg car to a 3 mpg car will take 3 stops to refuel just to reach the dealership.
posted by qvantamon at 6:56 PM on December 15, 2008


Who cares? This is just more rationalization that we don't have to give up cars as our usual mode of transport, and the auto industry as a "cornerstone" of our economy. (Yesterday I heard someone claim that we have to save the Big Three, because they're "part of our heritage". Like clean air and hitting people with rocks.)
posted by sneebler at 7:01 PM on December 15, 2008 [9 favorites]


So a person with a hybrid Civic can only be as smug to a standard Civic owner as a hybrid Tahoe owner can be to a non-hybrid Tahoe owner? I guess there is no point in buying a hybrid, then.
posted by 0xdeadc0de at 7:10 PM on December 15, 2008 [1 favorite]


e) bicycle
f) walk
g) move closer to work
h) work at home

seriously, the solution to the oil/pollution/health/social disaster is staring everyone in the face. it's like arguing over which is the most humane method of execution: if humanity is your primary concern, stop fucking killing people.
posted by klanawa at 7:11 PM on December 15, 2008 [12 favorites]


kenko- the absolute delta is the whole point.

Yes, utility increases monotonically with MPG. But it isn't linearly related, and the derivative of that nonlinearity tells us where our attention should be, both in terms of our personal purchases and what we prioritize for energy policy.

Why do we care so much about pushing hybrids/ alternative fuels right now? How about imposing the same efficiency standards on SUVs as are imposed on cars? How about putting stricter standards in place for semis? For a fixed amount of available political capital, the latter two give us a bigger environmental bang for our buck than the first.
posted by a snickering nuthatch at 7:12 PM on December 15, 2008 [9 favorites]


Which reduces my health risks more? Going from drinking a six-pack of beer a night to a single glass of red wine with dinner? Or going from sucking down a quart of vodka underneath a bridge to just having a few shots with my friends at the bar?

This is great. Can I use this new logic on everything?
posted by Navelgazer at 7:14 PM on December 15, 2008 [16 favorites]


seriously, the solution to the oil/pollution/health/social disaster is staring everyone in the face.

Or we could just kill half the population. Don't worry, it will be the half you don't know.
posted by Pastabagel at 7:14 PM on December 15, 2008 [2 favorites]


On the other hand, going from a 1 mpg car to a 3 mpg car is, in both absolute and percentage changes, a huge win!!!!

Option E) Become CEO of an major financial institution, run it into the ground, let the tax payers bail it out, retire with a multi-million bonus, build a custom 1mpg car, trade it for custom 3mpg on advice of PR firm. Sell 1mpg car design to military.
posted by Staggering Jack at 7:15 PM on December 15, 2008 [4 favorites]


Or we could just kill half the population.

This seems to be the solution favored by our environmentally-conscious drivers here in Chicago.
posted by enn at 7:18 PM on December 15, 2008 [7 favorites]


The 14 mpg car is more fuel efficient than the 50 mpg car, since the owner can't afford to go anywhere. Mr. Hummer stays home and eats Cheetos while Mr. Prius paints the town red.
posted by swell at 7:22 PM on December 15, 2008


For a fixed amount of available political capital, the latter two give us a bigger environmental bang for our buck than the first.

The thing is, a fixed amount of political capital is unlikely. Capital pretty much boils down to how much people love you. Because people love you, you can convince other lawmakers to act as you do, or else you will sic the hounds on them. So by pursuing things like hybrid cars, you (perhaps) gain more capital than you would be jacking up the minimum MPG. I don't know if that's true, of course. But a fixed amount of capital is a scenario that doesn't matter.
posted by Lemurrhea at 7:23 PM on December 15, 2008


33 mpg car, 10,000 miles. 303 gallons
50 mpg car, 10,000 miles. 200 gallons
save 103 gallons, 15% better savings than:
14 mpg car, 10,000 miles. 714 gallons.
16 mpg car, 10,000 miles. 625 gallons.
save 89 gallons

14 mpg car, 10,000 miles. 714 gallons.
50 mpg car, 10,000 miles. 200 gallons.
577% savings changing 14 for 50 mpgs.
posted by dances_with_sneetches at 7:24 PM on December 15, 2008 [8 favorites]


Oh right. I'd also like to point out that I love Cass Sunstein with a capital V.
posted by Lemurrhea at 7:25 PM on December 15, 2008


Option A reduces gas consuption by about 50%, and option B does so by about 14%.

Why do you think the percentage reduction is a significant measure? The proper measure is the absolute reduction.
posted by Mr. President Dr. Steve Elvis America at 7:28 PM on December 15, 2008 [1 favorite]


These guys need to come up with something a little more clever if they want to distract us from the real issues. I haven't read the book, it seems like some of their "nudges" are good, but on this one they are definitely part of the problem.
posted by snofoam at 7:37 PM on December 15, 2008


I'll tell you what saves ME the most gas -- not eating chili three meals a day! Whooee!
posted by Saxon Kane at 7:38 PM on December 15, 2008 [1 favorite]


I'm all for debunking the myth that "hybrid SUVs are stupid" (they're not, as he shows), but he really blows it with his silly argument against the European method of expressing efficiency (liters per 100 kilometers). That's almost exactly what he's arguing for in the rest of his article, but rejects it because ... it wasn't his idea?

Anyway, today's nominations give me Hope that all this will get a lot better real soon.
posted by intermod at 7:38 PM on December 15, 2008


The way to reduce gas consumption is to raise gas taxes. That's not going to happen in today's political universe so instead we'll talk about more efficient sport utility vehicles.
posted by rdr at 7:52 PM on December 15, 2008 [1 favorite]


[he] rejects it because ... it wasn't his idea?

Even though it would completely make people think the way he wishes they would, he rejects it anyway because it's in them crazy ass-backward furrin units.

Thinking in gallons per 100 miles would change American habits, I bet.
posted by rokusan at 8:04 PM on December 15, 2008 [2 favorites]


A 20% reduction in speed is worth a 50% reduction in fuel used to destination. Longer trip time reduces the number and distance of trips. Slower speeds means fewer collisions and less damage caused when they do happen. Enforcement is cheap and easy with new technology.
posted by Chuckles at 8:06 PM on December 15, 2008 [2 favorites]


Option A reduces gas consuption by about 50%, and option B does so by about 14%.
Why do you think the percentage reduction is a significant measure? The proper measure is the absolute reduction.
Actually, except when taking the premises of a strained line of reasoning out of context and going with them as gospel, the proper measure is absolute usage.
posted by Flunkie at 8:07 PM on December 15, 2008


D'oh, that should be a 33% reduction in fuel used to destination.
posted by Chuckles at 8:08 PM on December 15, 2008


you need to watch some clarkson. toyota prius vs. bmw M3, racing supercars economically, and if you really want, youtube and the bbc iplayer will have a million more such videos for you.
posted by krautland at 8:09 PM on December 15, 2008 [2 favorites]


Jesus, talk about the perfect being the enemy of the good.
posted by maxwelton at 8:11 PM on December 15, 2008 [1 favorite]


Also, why does no one ever take into account the environmental cost of the new car's construction? Cars can last almost indefinitely with proper care, and yet even "green" people think nothing of buying themselves a new car every three or four years.
posted by maxwelton at 8:18 PM on December 15, 2008 [1 favorite]


"It was one of the dullest drives of my life, but in the interest of science I stuck with it."
posted by Chuckles at 8:24 PM on December 15, 2008


Cars can last almost indefinitely with proper care,

Not once you get one of these cars they make now with motherboards and processors and shit. The hard drive goes crap in three years and the OS isn't forwards compatible and then before you know it you'll have to use one of them old fashioned paper maps to tell where you're going and the DVD to shut the kids up in the back won't work and isn't Blu Ray anyway and don't get me started on the the resolution of the reverse camera...
posted by spicynuts at 8:29 PM on December 15, 2008 [2 favorites]


Actually, except when taking the premises of a strained line of reasoning out of context and going with them as gospel, the proper measure is absolute usage.

Looking at absolute usage isn't very helpful for evaluating a program intended to save gasoline.

For example: Should we replace our current fleet of vehicles, which has an estimated average remaining useful life of three years and average unit salvage value of $4,500, with a fleet that will use 5 gallons of gasoline per 100 miles traveled, cost $20,000 per unit, and have a useful life of six years?

You have no idea, because you don't know how much gasoline the old fleet uses.
posted by Mr. President Dr. Steve Elvis America at 8:32 PM on December 15, 2008


e) other
posted by goodnewsfortheinsane at 8:32 PM on December 15, 2008


A 20% reduction in speed...Enforcement is cheap and easy with new technology.
You've got to be kidding. That's about as likely to make a comeback as prohibition. If the price of gas reflected its true cost, people would slow down on their own.
posted by scope the lobe at 8:33 PM on December 15, 2008 [1 favorite]


Has anyone here switched from normal tires to low rolling resistance tires to save gas?

No, because they also significantly decrease primary safety. Which is the bit that stops me from needing those rather expensive (and environmentally damaging to produce) airbags. Not to mention the environmental, and financial, costs of respraying my car and the replacement panels afterwards.

The way to reduce gas consumption is to raise gas taxes.

Rubbish. That has been demonstrated to be completely ineffective in many countries (including the UK) for years. The way to reduce petrol consumption is to legislate for more stringent emissions and accept the lead time required for the major volume of vehicles to hit the product life that will comply with it. This is not something that a knee jerk reaction will fix; only evolution will produce an effective and lasting response without unnecessarily crippling the lower earning populace.
posted by Brockles at 8:39 PM on December 15, 2008 [1 favorite]


I see that you missed the part where I said "except when taking the premises of a strained line of reasoning out of context and going with them as gospel".
posted by Flunkie at 8:44 PM on December 15, 2008


"The way to reduce gas consumption is to raise gas taxes."

"Rubbish."

Heh. I don't know (or really care) about UK. High prices has been very effective at reducing gas consumption in the US this past year.

And to all those people who say that people driving SUVs should start driving 50mpg cars (or riding buses), well high gas prices was actually convincing a lot of people to do that. But there are many who won't, despite you telling them otherwise (I know you'll be really disappointed to hear this). For these people, a hybrid SUV will have a large affect on gas consumption.

I always found it interesting that Ford is often criticised, yet they had one of the first American hybrids, and it was as SUV (the Ford Escape). It was based on Toyota's patent and very efficient. Why didn't we hear about it? I sometimes wonder if the Ford engineers got the message, but the Ford sales and marketing guys are still old school.
posted by eye of newt at 9:01 PM on December 15, 2008


Chuckles
A 20% reduction in speed is worth a 33% reduction in fuel used to destination.
Citation? 30mpg at 65mph = 45mpg at 52mph? Or am I missing something?
Longer trip time reduces the number and distance of trips.
If you go slower you don't have to go so far or go so often? Or are you suggesting that it would discourage discretionary travel (vacations etc.) rather than business travel requiring physical presence? I can't quite follow this line of reasoning - perhaps it's a joke and I'm not getting it?
FWIW My observation in traveling in the Western States during the 55mph speed limit days was that many trips required an extra day on the road (with the concomitant expenses) and saved about 5% in fuel.
posted by speug at 9:27 PM on December 15, 2008


I see that you missed the part where I said "except when taking the premises of a strained line of reasoning out of context and going with them as gospel".

The first draft of my comment actually indicated that I didn't know what you meant by that, but I took it out, because I thought it seemed combative.
posted by Mr. President Dr. Steve Elvis America at 9:27 PM on December 15, 2008


Jesus, talk about the perfect being the enemy of the good.

Ya know, I first read that sentence eponysterically. I think I've been packing for my move too long. Time to hit the hay.
posted by IAmBroom at 9:37 PM on December 15, 2008 [1 favorite]




My bicycle gets (roughly) 10 miles to the gallon, but I'm measuring in beer, not gas.

/snark
posted by Panjandrum at 9:44 PM on December 15, 2008


What I meant is that if I got drunk and pissed in the village well once last year, and you got drunk and pissed in the village well every night last year, what is important is not that you reduce your piss-in-the-village-well quantity this year as much as I reduce mine. What is important is that you've got to stop pissing in the village well.
posted by Flunkie at 9:45 PM on December 15, 2008 [7 favorites]


Six months ago, I moved from an apartment 30 minutes from work to an apartment 2 minutes from work.

Six hours ago, I traded in a 2000 Ford Taurus that got 17city/26highway mileage (when it was new - lord knows how badly it was doing with 125K miles on it) for a 2009 Toyota Yaris which gets 29city/36highway mileage.

And that's all great, but you know what I'd really like though?

A group hug.
posted by BrianBoyko at 9:48 PM on December 15, 2008


speung - Slow travel reduces discretionary travel, especially things like short trips for individual tasks that could be grouped together in a single longer-but-shorter jaunt on a later day. Why walk to the grocery and back today when I know I'll be walking to the barber next door to the grocery tomorrow? If I could teleport, there would be no reason not to hit the grocery today and the barber tomorrow, if I'm walking, there's every reason. If I'm taking a car, the cost-benefit is somewhere inbetween, but often on the 'teleport' end of the scale.

Also, force exerted by the engine to move a car is mainly a necessity of air resistance, which increases as the square of one's velocity relative to the wind. So you get this parabolic graph of force required to overcome air resistance; let V be the velocity relative to the wind, k the coefficient of drag, and F the force required to overcome air resistance.

Then:
F ~ k*V^2
Set V' := 0.8*V => F' ~ k*(0.8*v)^2 = k*0.64*V^2

So a 20% reduction in speed yields a 36% reduction in the required force, a little bit better than the 33% above, but without worrying about things like rolling resistance, so 33% is probably pretty realistic.

(I don't drive, but do ride a bicycle, where such calculations are even more important. Exercise: in a cross-country bike tour, how many calories does silly-looking tight-fitting clothing save?)
posted by kaibutsu at 9:59 PM on December 15, 2008


Citation? 30mpg at 65mph = 45mpg at 52mph? Or am I missing something?

Drag force goes up by the square of velocity. That means power to maintain a given speed goes up by the cube. However, the faster you go the quicker you get to your destination, and that relationship is linear, so we are back down to the square. At highway speed, something around 90% of losses go to fighting aerodynamic drag (ya, I pulled that number out of my ass, but it is probably pretty damn close to correct), so I just neglect the other 10%. From there, it is just math.

Thing is, a car spec'd at 30mpg isn't spec'd at 65mph. I'm not a car guy, but my understanding is that they spec the fuel economy at the cars most efficient speed, or at a reasonable highway minimum speed, or whatever thing they can get away with that isn't honest.

If you like, here's a citation, but they get the physics wrong, so...
One reason is that aerodynamic drag increases exponentially the faster you drive;
Nope, it increases by the square of velocity, as I said.
(they also say that only 50% of engine power goes to fighting drag, I don't believe them)

Here's a better citation. This one also says only 50% of engine power goes to fighting drag, so perhaps that actually is the truth, but I'm still very suspicious.

Anway, while we are on the topic of how speed burns gas. Speed in city driving wastes gas just as badly as speed on the highway. Hit the gas to rapidly accelerate and then jam on the brakes at the next red light.. not efficient :P

And another interesting note. Apparently shipping by boat is actually quite inefficient, fuel wise. Like, worse than trucking or rail. Of course boats go slower than trucks or trains, but they are ploughing through water, so the drag is much higher!
posted by Chuckles at 10:22 PM on December 15, 2008


Exercise: in a cross-country bike tour, how many calories does silly-looking tight-fitting clothing save?

As someone who no longer owns a car, I would like to rephrase the question: how much time do I lose changing clothes and how many women do I fail to pick up by wearing silly-looking tight fitting clothing?

It's really a social cost-benefit ratio of strapping on the spandex vs. rolling up one pant leg.
posted by Panjandrum at 10:26 PM on December 15, 2008


i) trading in a 14 mpg SUV for a 100 mpg SUV
posted by flabdablet at 10:31 PM on December 15, 2008


Here's another article on engine efficiency that goes a bit beyond my mechanical/engine knowledge, but reads as completely plausible.
posted by Chuckles at 10:33 PM on December 15, 2008


Ahh, here's a good one: What speed should I drive to get maximum fuel efficiency.
posted by Chuckles at 10:39 PM on December 15, 2008


kaibutsu: ... Exercise: in a cross-country bike tour, how many calories does silly-looking tight-fitting clothing save?).

About 25% as measured in winter clothing v.s. summer clothing on a sweet recumbent bike. Here's a calculator that lets you easily compare various things like hands on top of drops v.s. bottom of drops. It also lets you change the "effective drag area" so interested readers can estimate the cross-country problem you posed.
posted by ecco at 10:40 PM on December 15, 2008


even "green" people think nothing of buying themselves a new car every three or four years

This "green" person wouldn't even contemplate such a ridiculous expense. I drive an 850cc, three-cylinder 1991 Daihatsu Mira. If I keep the speed below 80 km/h and drive smoothly, it regularly does better than 5 litres / 100 km. I expect I'll keep it until I can buy a similarly sized plug-in electric.
posted by flabdablet at 10:46 PM on December 15, 2008 [1 favorite]


Despite the Discovery Channel Jazz, that is actually a pretty interesting video; thanks flabdablet. Calling it an SUV is kind of silly though..

Exercise: in a cross-country bike tour, how many calories does silly-looking tight-fitting clothing save?

Forget tight fitting clothing, how about flab?
Somewhere on that page, they point out that decreasing bicycle mass has 1/4 the effect of decreasing rider mass :)
posted by Chuckles at 10:51 PM on December 15, 2008


Chuckles: Thank you for the response. The combining of trips from several short to one long is something many people already practice simply because it saves money and time - so that's certainly valid.
As to the equations, however, they simply don't work in practice.
Driving 200 miles at an average speed of 75mph the car gets about 30mpg. Driving the same 200 miles at an average speed of 60 mph (a 20% reduction) produces 32mpg.
I have observed savings of this order of magnitude in several cars in a lot of long distance driving and I have never heard of anybody getting 40mpg (let alone 45mpg) by simply reducing speed.
I have no idea why the equations do not apply to this situation but they don't.
Somewhat off-topic:
The biggest waste of gas, in our area at least, are the stop signs and stop lights where one gets precisely 0mpg. The system was designed by a sadistic traffic engineer to "calm the traffic" by de-synching the lights - which in turn maximizes delay times. He left town one step ahead of the lynch mob - but his legacy remains.
posted by speug at 10:52 PM on December 15, 2008


Driver A has a 50 mpg car yet drives to work alone.

Driver B has a 18 mpg car but shares his commute with another rider. One less car shared mpg.

Seems like their should be a reasonable calculation for a #of riders + mpg. (no math for me tonight)

One person one car bad bad bad.
posted by pianomover at 10:52 PM on December 15, 2008


My car gets about 600km to the tank. I'm very happy with that.
(Just don't ask how big the tank is.)
posted by aeschenkarnos at 10:55 PM on December 15, 2008


Yeah, the 50% number sounds highly suspect to me, as well. Some numbers from cycling:

"At cycling speeds greater than 15 mph, the energy needed to overcome AIR RESISTANCE greatly exceed those of the rolling and mechanical resistance in your bike. For example, in going from 7.5 mph to 20 mph:

* mechanical resistance increases by 225%
* rolling resistance by 363%
* air resistance by 1800%."

Unless most cars have ridiculously low drag coefficients or extremely clunky parts, I would guess that drag would dominate the force equation by 35mph, and render everything else irrelevant by the time we got to 55.

(Of course, internal combustion engines are extremely inefficient. Wikipedia: 'Most steel engines have a thermodynamic limit of 37%. Even when aided with turbochargers and stock efficiency aids, most engines retain an average efficiency of about 18%-20%.')
posted by kaibutsu at 11:00 PM on December 15, 2008


As much as I love my 33 mpg car (quite a bit), I would still trade it in for a 50 mpg car if it meant I could get from college to home and back on a quarter of a tank instead of an eighth. *

Anyways, why do something half assed when you can do a better (if infinitesimally) job of it.





*precise fractions are for suckers
posted by rubah at 11:06 PM on December 15, 2008


Calling it an SUV is kind of silly though

Because?
posted by flabdablet at 11:09 PM on December 15, 2008


From what they show in the video, it is the size of a Honda Civic.
posted by Chuckles at 11:15 PM on December 15, 2008


Driving 200 miles at an average speed of 75mph the car gets about 30mpg. Driving the same 200 miles at an average speed of 60 mph (a 20% reduction) produces 32mpg.

If power use is 50% drag and 50% everything else at 60mph, then 75mph would take 28% more fuel. Your seeing a 7% increase in fuel use.. It doesn't add up.. However, if you were talking 62mph vs 72mph, and a 50/50 split again, you would come out at 8% increase in fuel use -- which is pretty close to what you observe.

I'm damned surprised that power splits 50/50, but I can see some reason.. Cars are far more aerodynamic than bikes (unless you are talking recumbent with cowling). It is another reason why SUVs are a menace though, because they aren't just bigger than cars, they are less aerodynamic too (normally).
posted by Chuckles at 11:29 PM on December 15, 2008


rokusan: Thinking in gallons per 100 miles would change American habits, I bet.

As an American living overseas, I'd take that bet. Changing the method of measurement doesn't clarify anything. When I see that our Golf uses 4.7 liters every 100 km, I don't know how good that is. I have to convert it to MPG to get a feel for it, and that's a pain.

What does change habits, however, is fuel that costs $8-10 a gallon. This works even if you drive a fuel-efficient car.
posted by moonbiter at 12:09 AM on December 16, 2008


Rubbish. That has been demonstrated to be completely ineffective in many countries (including the UK) for years.

Obviously people will use less of something once a price reaches a certain threshold. People used much less gas this summer when it was $4 then they do now.
posted by delmoi at 12:26 AM on December 16, 2008


Obviously people will use less of something once a price reaches a certain threshold.

go on vacation to a high-gas-price country like ... oh, how about germany? yes, that'll do. then take a look at the various autobahnen and check out what kind of cars you see. or how many.

higher gas prices will make some people not drive as much but that does not mean that the higher they go, the less people drive. there is a limit to that and it's the number of poor people embarking on gratuitous (aka. pleasure) trips.

oh yeah, traveling by rail isn't a cheaper alternative, so without a better alternative raising gas prices ends up hiking inflation and not much else.
posted by krautland at 12:35 AM on December 16, 2008


higher gas prices will make some people not drive as much but that does not mean that the higher they go, the less people drive.

Again, people really did drive less when gas was more expensive, and they drive more now. So saying "it won't happen" is entirely counterfactual. It also affects people's choice in vehicles (making them more likely to buy higher efficiency vehicles).

Pointing out that people drive around a lot in Germany despite high gas prices doesn't really illustrate anything, because there's no control. You can't compare their driving now to what they're driving would if gas prices suddenly dropped.

But in the U.S. you can do that, because gas prices underwent a major, major fluctuation in a short amount of time. They spiked up to $4 in a few years, and then dropped to, what, $1.60 or whatever in a few months. That's about as close to an ideal economic experiment as you'll ever get. And what does it show? That people drove less when gas was more expensive, and now that's its cheap they're driving more.

Not too surprising.
posted by delmoi at 1:11 AM on December 16, 2008 [2 favorites]


(And it's not like people weren't driving at all, the marginal change wasn't that great, but it was certainly there)
posted by delmoi at 1:11 AM on December 16, 2008


But in the U.S. you can do that, because gas prices underwent a major, major fluctuation in a short amount of time.

So it could be argued that the delta in price is the deterrent.
posted by pompomtom at 1:39 AM on December 16, 2008


So, the savings between higher and lower MPG cars is negligible despite the fact that a 10mpg car burns 1/5th the gas of a 50mpg car? I think I've seen this kind of math used elsewhere recently.
posted by Pseudology at 2:02 AM on December 16, 2008


BrianBoyko: Six months ago, I moved from an apartment 30 minutes from work to an apartment 2 minutes from work.

That's the best way to reduce the amount of gas you burn. You now get many more commutes per 100 dollars and you added about an hour a day to your free time. (That's assuming you still even bother to drive; unless you drive like a maniac, a two-minute drive has to put you within bicycling range of work.)
posted by pracowity at 2:44 AM on December 16, 2008


go on vacation to a high-gas-price country like ... oh, how about germany? yes, that'll do. then take a look at the various autobahnen and check out what kind of cars you see. or how many.

Yes, but then check the fuel efficiency data. A 3L BMW (which is a larger engine than most sold in Europe) has a fuel economy similar to a Saturn Aura (automatic) or a Ford Fusion. Note that the Ford Focus, which is sold widely in Europe, has significantly better figures*. That's before you even get into the diesel/petrol split in Europe versus the US. I would argue that fuel pricing does drive fuel economy.

*Figures from www.fueleconomy.gov
posted by Jakey at 2:48 AM on December 16, 2008


Congressional Budget Office study (January 2008): Effects of Gasoline Prices on Driving Behavior and Vehicle Markets (pdf):
CBO has found the following specific effects in its analysis:

- Freeway motorists have adjusted to higher prices by making fewer trips and by driving more slowly. CBO analyzed data collected at a dozen metropolitan highway locations in California, along with data on gasoline prices in California, to identify changes in driving patterns. On weekdays in the study period, for every 50 cent increase in the price of gasoline, the number of freeway trips declined by about 0.7 percent in areas where rail transit is a nearby substitute for driving; transit ridership on the corresponding rail sys- tems increased by a commensurate amount. Median speeds on uncongested freeways declined by about three-quarters of a mile per hour for every 50 cents the price of gasoline has increased since 2003.

- After increasing steadily for more than 20 years, the market share of light trucks (including sport–utility vehicles and minivans), relative to all new passenger vehicles, began to decline in 2004. As a result, the average fuel economy of new vehicles has increased by more than half a mile per gallon since 2004 (because light trucks tend to be less fuel efficient than cars).

- Used-vehicle prices have shifted, reflecting changing demand, particularly with respect to fuel economy: The average prices for larger, less-fuel-efficient models have declined over the past five years as average prices for the most-fuel-efficient automobiles have risen.
posted by pracowity at 3:44 AM on December 16, 2008 [2 favorites]


go on vacation to a high-gas-price country like ... oh, how about germany?

Rather than go there and use your no-doubt highly scientific powers of observation, you could simply search the web for per-capita gasoline consumption. According to the first reference found, they burned less of the stuff than Switzerland or the UK, and a fair bit more than France. Of course none of Europe comes close to matching America in this statistic.

Litres to 100km is easy to relate to once you get used to it. It's usually used in Canada now, finally replacing American MPG which my highly-scientific powers of observation tell me was still more common until a few years ago. Lately I observe that car ads on television are starting to make fuel-economy claims in miles per Imperial gallon, as in the UK, presumably hoping that people will get confused and think they're talking miles per US gallon, the more familiar measure. I wonder how many people fall for it.
posted by sfenders at 4:35 AM on December 16, 2008


I like how the example for the FPP does not make the point it's trying to make. I guessed 33-50 and was right by 13%.
posted by a robot made out of meat at 5:26 AM on December 16, 2008


My bicycle gets (roughly) 10 miles to the gallon, but I'm measuring in beer, not gas.

Is that ten miles in a straight line, or counting all the S curves?
posted by rokusan at 5:43 AM on December 16, 2008


Also, force exerted by the engine to move a car is mainly a necessity of air resistance

Agreed. Well, actually not really. Especially the 'mainly' aspect. All the armchair engineers that leap on this constantly, fail to acknowledge (or perhaps don't know) that air resistance is by no means the single biggest drag or resistance to movement of a car - particularly below 40-45mph it is almost irrelevant. Consequently, any suburban/city driving and any journey slower than that speed can't use the 'going slower is always less fuel efficient' argument. It simply isn't true.

As proven several times elsewhere on here, too, there is not necessarily any advantage in slowing down at higher speeds, as the peak economy of cars is not always at the same speed, nor is it always at a low speed. Sometimes, it isn't even below the speed limit. It is a fallacy oft repeated on here, that people in the know get pretty bored of seeing again and again. It depends on the gearing, power output of the car and also the drag coefficient of the car. Not just the drag coefficient by any means.

Aerodynamic force and the drag induced does increase at a great rate with speed. Yes. But only at the point when it is as high or higher than the massive internal frictions and rolling resistances in the car does it even matter. A very sharply rising force in relation to speed only makes speed important if that force, rather than the linearly rising mechanical drag forces, are the presiding issue.

Rather than go there and use your no-doubt highly scientific powers of observation, you could simply search the web for per-capita gasoline consumption.

That is a completely irrelevant number unless you factor population density and the average mileage from areas of population to items of need/interest. People drive less in Germany mainly through better urban planning, it seems to me from my knowledge of Europe. The UK, also, wins against the US on that score (as does almost any European country).

Again, people really did drive less when gas was more expensive, and they drive more now. So saying "it won't happen" is entirely counterfactual.

You can't possibly hope to repeat the shock factor, though. Slow, gradual increases in fuel prices are unlikely to have any effect on any but the poorest families that simply don't have the cash to fill the car up anymore - this has been demonstrated all over Europe as being true. It only, in the US, affected the vast majority of people that drive constantly just because they can afford it because the cost of doing so becomes suddenly, significantly and glaringly, obvious. You can't sustain that kind of shock awareness.

That is why I invoked the UK example. You'd have to double the fuel prices in the US at least every year to keep that same kind of shock factor and that simply isn't tenable. Higher fuel prices have seemingly driven the industry to better economies, but that has by no means been the main reason that the Car Industry have done it. In the US they just haven't bothered because they haven't had to offer these more economical engines.

Here's why - the Car Industry doesn't really give two shits how much fuel is. Seriously. They only care if you buy their cars. It doesn't matter to them if you drive 2 miles a week or 200. The ONLY thing that the car industry has to respond to is legislation, it then tailors that response, or just plain spins the result, in accordance with marketing trends. The high rate of change of emissions regulations is the sole reason for increased economy in cars. Not the price of fuel at all. By far the most effective way to get cars to burn less fuel is to make them unsellable if they don't. The buying public are only marginally influenced by fuel economy, so making the entire choice available of cars physically available to them have a lower average fuel burn through emissions regulations is really the only way to do it effectively.

Don't mistake the current accelerated response from the US public for better economy with any direct correlation with 'fuel prices = driving less and people wanting better MPG' being true. The trend is exaggerated at present through the US car market having to suddenly catch up with Europe - something it has avoided doing for years through the exact same stupidity and a lethargic market that has caused the current woes of the Big Three. It is a reaction that has been artificially suppressed for a very long time by the car companies and their effective lobbying controlling the market far more than the US public realised - the rate of change is consequently artificially high to recover from this initial suppression.
posted by Brockles at 5:53 AM on December 16, 2008 [1 favorite]


Drop in driving deaths linked to higher gas prices
Faced first with high gas prices and now with a slowing economy, drivers can look to a thin silver lining on a gloomy 2008 – the number of people dying in car crashes has dropped sharply this year across North America. Many of the largest Canadian police forces see the trend, most significantly in Ontario, where provincial police have seen deaths drop 30 per cent from the same time in 2007. Double-digit percentage drops have also been seen in British Columbia and Manitoba. ...

Soaring gas prices throughout much of the year caused people to drive more slowly and less often, resulting in fewer serious crashes, academics say. ...

Last week, the National Highway Traffic Safety Administration in the United States said there were 31,110 fatalities in car crashes through the end of October, 2008 – an overall drop of 9.8 per cent since the same time last year and on track to be the lowest total recorded since they began measuring the statistic in 1966. ...

[Grabowki's] study found that when prices are sustained for two years, every gas-price jump of 10 per cent leads to a two-per-cent drop in auto fatalities.
See also:
Is there a silver lining to rising gas prices?
; Gasoline prices and motor vehicle fatalities (abstract only);
High gasoline prices and mortality from motor vehicle crashes and air pollution
(abstract only)

If the Globe & Mail article expires, there's a similar article in Market Watch.

(On preview: yes, this effect may be most marked in car-loving North America versus Europe, but it is an effect.)

And while Jeremy Clarkson is a hell of a driver and obviously knows a lot about cars, he's also a showman who doesn't always feel compelled to be scrupulously honest. That Top Gear excerpt with the Prius is about as misleading as making a stakes-winning quarter horse run against the cheapest thoroughbred claimer for a mile instead of a quarter mile. The Prius attains its high mpg rating through switching to the electric motor instead of the gasoline engine in stop and start city driving, with regenerative braking recharging the electric motor. It is not at its most efficient in non-stop highway driving. There are reasonable arguments to be made about the environmental impact of the batteries, or about what really is the best or typical mileage to expect from a Prius. But the stunt pulled on Top Gear tells us nothing useful.
posted by maudlin at 6:10 AM on December 16, 2008


Again, people really did drive less when gas was more expensive, and they drive more now.
did you read what I wrote? people will cut back on trips they can cut back on easily and then it stops. they will still drive to work. they will still drive to the store. the effect plateaus in spite of continuously raising prices. at a certain point all you're doing is taking money out of the populus.

You can't compare their driving now to what they're driving would if gas prices suddenly dropped.
wrong. you just need to go back a decade.

Note that the Ford Focus, which is sold widely in Europe, has significantly better figures*.
it's also a fairly nice car that ford should have put onto the US market a long time ago. also worth selling in the US: VW's polo, lupo or golf fsi.
posted by krautland at 6:24 AM on December 16, 2008


Math before coffee makes my head hurt, but this is an interesting blog and I'm glad it was posted (regardless of the truth of the assertions).
posted by desjardins at 8:18 AM on December 16, 2008


This link showing fuel consumption by country (posted by sfenders) is fascinating.

For instance, it shows that - despite having just about the same population density as the US in built up areas, and substantially less population density through low-density areas - both Canada and Australia use less gasoline per person:

For 1990, 2000 and 2003 (in that order) - Motor gasoline consumption per capita
Units: Liters per person

Australia: 995.4 - 926.6 - 907.7
Canada: 1,168.7 - 1,182.7 - 1,203.7
United States: 1,542.1 - 1,633.9 - 1,635.2

Notably - consumption went down in Australia (by almost 10%) over the 1990s, while it went up slightly in Canada and the US.

I don't know what the gasoline/car culture in Australia is like, but I know that Canada - despite having less overall population density and a very similar culture and economy in most ways - has much higher gas prices than the US. And this shows up in gas usage which was only some 73% of the American usage in 2003, while the Australian was only some 55%.

I had assumed that all three would be similar, but American usage must be much more cultural than I had realized - a culture fed by low gas prices.
posted by jb at 8:32 AM on December 16, 2008


Don't mistake the current accelerated response from the US public for better economy with any direct correlation with 'fuel prices = driving less and people wanting better MPG' being true

In other words "don't pay attention to the facts. They are irrelevant--listen to me!"

In America people frequently drive several hundred miles--as often as every weekend, and even for the daily commute. In many places in Europe this would take you out out of the country.

These several hundred mile trips would quickly bankrupt even the upper middle class with high prices and a gas guzzling SUVs. Talking about 'only the poorest will cut back on their driving' shows an amazing misunderstanding of the typical situation of the average American.

Note that the head of the Saudi oil industry frankly admitted in Business Week that the reason Saudi Arabia completely ignored the OPEC vote and started pumping oil like crazy to lower oil prices is that they are worried about Americans reducing their dependency on oil and hurting their market in the long term. Iraq, Iran, and Venezuela were quite upset (they have immediate short-term needs for the cash) and said that they were going to cut back on production, but he said it doesn't matter since all their oil put together was a fraction of what Saudi Arabia has.
posted by eye of newt at 8:35 AM on December 16, 2008


That is a completely irrelevant number unless you factor population density and the average mileage from areas of population to items of need/interest. People drive less in Germany mainly through better urban planning, it seems to me from my knowledge of Europe. The UK, also, wins against the US on that score (as does almost any European country).

Canada does not have substantially better urban planning than the US, and lower population density overall (though I would say that it is quite similar in built up areas like southern Ontario). If it has fewer exurbs, it is because of long-running high gas prices, not "shock factor". Steady higher gas prices have lead to a lower consumption rate/capita, even in a country where you may have to drive 6 hours to reach the next major city, and some people do commute 1-2 hours each way by car.

I would really like it if someone who knew Australia could comment. What is the urban planning there like? The car culture? Was there high gas prices c2003, or pushes from the government for more fuel economy?
posted by jb at 8:39 AM on December 16, 2008


I don't think comparing gas consumption in the US to Europe is fair at all, since European cities are much denser and the public transport system is (overall) better. I sure as hell wouldn't drive in Paris. I took a taxi once and thought I was going to die. If you live outside of New York, San Francisco, and a few other major US cities, driving is far less optional.

It'd be lovely and wonderful if the US had the density and public transportation infrastructure that Europe has, but we don't, and are unlikely to in the near future.
posted by desjardins at 8:46 AM on December 16, 2008


ugh, I see someone made my point already.
posted by desjardins at 8:47 AM on December 16, 2008


they will still drive to work. they will still drive to the store. the effect plateaus in spite of continuously raising prices.

They will share rides. They will take alternative modes of transportation. They will buy two or three times as much per store trip but go to the store a half or a third as often. They will go shopping with neighbors and friends. They will choose homes closer to where they have to go (schools and work and stores) and they will walk or bicycle for some of these trips.

The trick to faster change is to put the extra gas tax revenues into buses and trains and bicycle paths, so that the alternatives become better and better as driving becomes worse and worse. Unless you drive for the sake of driving (and are willing to pay through the nose for your pleasure), you are not going to keep driving every day when everyone around you is taking clean, cheap, frequent, safe, dependable, comfortable public transportation to the same destinations.
posted by pracowity at 8:49 AM on December 16, 2008


It'd be lovely and wonderful if the US had the density and public transportation infrastructure that Europe has, but we don't, and are unlikely to in the near future.

What you should not ignore is how often people move. In the US, each person changes homes about a dozen times over their lifetime. One in six are moving each year. Moving is not a big deal.

It wouldn't take very long for people to rearrange their lives. They were going to move anyway. They were going to choose a city or a suburb, a house or an apartment, a nearby job or a distant one, a nearby school or a distant one. With different financial pressures, their choices will be different. The US will have the population density and public transportation infrastructure of Europe in a few years if it's too expensive to live otherwise.
posted by pracowity at 8:58 AM on December 16, 2008


desjardins : If you live outside of New York, San Francisco, and a few other major US cities, driving is far less optional.

Yep. And if you live in the midwest, you aren't going to get much bicycling done for about 1/3rd of the coldest parts of the year. I would love it if I could make use of public transportation like light rail, but it was decided that no one here really, actually wanted it.

Because who would want to be able to get from the suburbs to the metro area cheaply and cleanly, right? That's just crazy-talk.

That said, I just switched cars, and my "new" '99 Sentra gets 8 mpg less than my '98 Saturn, and it pisses me off to no end.
posted by quin at 9:22 AM on December 16, 2008


it was decided that no one here really, actually wanted [light rail].

You mean Waukesha County didn't want it, because they didn't want "those people" coming out to the suburbs.

The US will have the population density and public transportation infrastructure of Europe in a few years if it's too expensive to live otherwise.

I do not think gas prices will be the determining factor here. Way too many people don't want to live in cities because of the noise, crime, etc. It's going to take extremely high prices before people give up the "American Dream" en masse. Europeans, in large part, haven't had the option of McMansions with half-acre yards, so increased density is not the psychological shift that it would be in the US. There's also large numbers of white Americans who don't want to live anywhere near minorities (the same may be true in Europe, but there's still less space overall). Plus, factor in the failing public school systems.. there's a lot that would have to change in order to entice massive population shifts towards cities, and gas prices alone won't do it.
posted by desjardins at 9:38 AM on December 16, 2008


Yep. And if you live in the midwest, you aren't going to get much bicycling done for about 1/3rd of the coldest parts of the year. I would love it if I could make use of public transportation like light rail, but it was decided that no one here really, actually wanted it.

The greater Toronto area is no warmer than most of the mid-west, and the suburbs have terrible transit. And this is one of the densest bits of Canada.

So why are we using 75% of what the US uses?

It's not just landscape.

Basically, I'm asking - can we stop talking about Europe already? Yes, we all know it is very densely populated, and the pastries are excellent. But I just pointed out that the US is using nearly twice as much motor vehicle gasoline as Australia. It's not exactly a small country with dense rail networks like the UK.
posted by jb at 9:41 AM on December 16, 2008


Oh - I would also point out that the rail system is, if anything, worse in Canada than in the US. I would take Amtrack over VIA anyday.

But Greyhound Canada offers much better service than Greyhound US - true, Greyhound US sets a very low bar, but Greyhound Canada is really quite a nice, pleasant company to deal with and a comfortable way to travel.
posted by jb at 9:44 AM on December 16, 2008


The greater Toronto area is no warmer than most of the mid-west, and the suburbs have terrible transit

Ha! Mississauga Transit and York Region have far, far better transit than most US suburbs. Plus they interconnect to the TTC and almost everyone using them is going downtown anyway. Plus the GO train is a big deal in terms of getting people into the downtown core.

Also, litres per 100 km isn't hard once you get used to it and have some benchmark numbers of what's good and what's bad. 4.7 l/100km is GREAT. My Jetta used to get around 8. I think some of the higher-end VWs have fuel economy gauges on the dashboard so you can see your fuel economy improve as you go on long highway drives.
posted by GuyZero at 10:06 AM on December 16, 2008


I've used Missisauga Transit, and it does NOT connect well with the TTC. It can take 2-2.5 hours to travel what would be a 20-30 minute drive in the GTA once you have to leave the (admittedly excellent) TTC zone. And GO trains only run one-way: into the city. Anyone working in the growing businesses, offices and industries of the suburbs cannot use GO trains to travel to them. They must drive.

But fact is, if the suburbs of Canada have better transit - that is clearly a cultural response, not a landscape/urban planning one. Communities have supported better (though not very good) transit, because they wished to drive less - or, more accurately, many Canadians simply cannot afford to drive. This sucks (being one of those Canadians), but it does show how higher gas prices can lead to lower gas consumption, even in a spread out, New World style landscape, and how American gas usage is not simply a function of their landscape, but also of their cultural and social choices.

(I would say that Mississauga Transit is notably cheaper and better than transit in Cambridgeshire, UK, even where quite densely populated. They wanted to charge me £2+ (over $4) to go maybe 3-4 km, just because I had to switch buses to go in a different direction. Stagecoach should be strung up.)
posted by jb at 10:27 AM on December 16, 2008


re: carbon taxes as a disincentive for fuel consumption.

in BC, the government's much-ballyhooed carbon tax is used to help subsidize the natural gas drillers to the tune of $200 million a year (they don't need it). the NG is piped over to alberta where it's used to render bitumen, which gets piped down to the US. bitumen is one of the dirtiest, most destructive sources of oil known to man.

BC's "green" government supports the federal conservative party, which is headed by the son of the former captain of imperial oil and which supports completely unregulated oil-rush in AB and SK which is canada's biggest greenhouse-gas producer and the largest mining project in the world.

green initiatives are not always what they seem.
posted by klanawa at 10:39 AM on December 16, 2008


The cheaper gas is, the more likely you are to drive.

I'm still happy with my motorcycle. Gets me where I need to be, carries enough groceries for my needs, and gets ~50mpg.
posted by Eideteker at 10:42 AM on December 16, 2008


Nit: there is no anti-metric bias in the article. His complaint about liters per 100 kilometers is that the magnitude of the value is less than ideal. Granted this is poor writing, he starts out by saying the reciprocal is the problem and then slips in that oh hey they actually do use the reciprocal in Europe and that doesn't work well either. But 10000 miles is a nice unit that can be multiplied by a small number (generally) to get gallons per year.

I have a hard time supporting CAFE over gas taxes. It's just so fucking lame. It doesn't measure gas consumption at all. WTF?

(At least CAFE does use harmonic means of mpg AKA standard means of gpm.)
posted by Wood at 10:55 AM on December 16, 2008


Anyone working in the growing businesses, offices and industries of the suburbs cannot use GO trains to travel to them. They must drive.

This is an issue that I think transit planners everywhere are facing: that the old pattern was one of a central work area ("downtown") where everyone went to from the suburbs. Feeder transit systems are much simpler to run as they only have to take people along one set of paths, twice a day. The GTA has been very good at this for a long time - my dad used to take Markham Transit & the TTC on what would have been a 21 km drive every day. But if you wanted to, say, take public transit from High Park to where ATI/AMD is out in Markham or out to where the banks have their new buildings out in Mississauga, absolutely, you're screwed. I think the city of Toronto is doing itself a long-term disservice by not zoning more high-density commercial real estate in the city to keep office space cheap. In the long term moving these offices out to the periphery of the city only causes more strain on resource that cannot be easily expanded, specifically local highways.
posted by GuyZero at 11:21 AM on December 16, 2008 [1 favorite]


traveling by rail isn't a cheaper alternative

For tourists, traveling by rail in Germany is absolutely a cheaper alternative.
posted by oaf at 11:57 AM on December 16, 2008


Mississauga Transit and York Region have far, far better transit than most US suburbs. Plus they interconnect to the TTC

You've got to be kidding. Since when is paying $6 each way to go between Highway 7 and Sheppard a good deal?
posted by oaf at 12:00 PM on December 16, 2008


In most US suburbs you wouldn't be able to do it at all, that's all. But sure, they're a bear to use if you're not commuting downtown and even then they sort of stink. But they stink less relatively speaking.
posted by GuyZero at 12:06 PM on December 16, 2008


In most US suburbs you wouldn't be able to do it at all

I'm not sure where you're getting that idea. If we're comparing Toronto suburbs to New York suburbs, Toronto loses that contest, both on price and on service.
posted by oaf at 12:56 PM on December 16, 2008


good grief. The ONE set of suburbs in North America with decent transit. Yes, NYC has a fantastic transit system. LA, Boston, SF Bay Area (maybe Chicago) are all roughly on par with the GTA in suburban transit, IMO. Beyond that good luck.

At any rate, all this proves is that old cities have better public transit infrastructure than new cities which isn't that much of a revelation. Newer cities have bigger highways.
posted by GuyZero at 1:20 PM on December 16, 2008


Your comment at 3:06 shouldn't have specified the U.S., then, because it applies to Canada as well.

I can't think of anywhere in the U.S. where your fare doubles just because you cross a street.
posted by oaf at 1:36 PM on December 16, 2008


The precipitous drop in gas prices (from upwards of $4 to less than $1.50 in what, 60 days?) has honestly not changed my life one bit. I still pump gas and say, "Gadzooks! Look at that price!"

I'm a bus rider.
posted by dirtdirt at 1:50 PM on December 16, 2008


I live in one Chicago suburb and work in another. There is no way for me to get to work via public transportation. The lack of density can't possibly justify the cost of putting in transport. For chrissakes, I pass horse farms on my way to work.
posted by desjardins at 1:55 PM on December 16, 2008


Hello, here's a token Australian, commenting about our car culture, urban planning, petrol prices etc, so you can try to make a fair comparison. Though my main US reference points are popular culture, I can opine more authoritatively about european comparisons.

Firstly, petrol prices. Used to be about $1.50/l (suggest PPP comparator of US$5/gal), now back down to $1 (say US$3.50). Diesel is gaining popularity due to adoption of EURO4 standard, and lots of small euro oil-burners are on the road now. Also, LPG available in cities at 60c/l, though mostly used by the taxi fleet.

Car culture was dominated by Ford and Holden (which is GM). Classic Aussie car was the Holden Commodore (sold as a Pontiac G8 I believe), but there's huge diversity in the cities now, biggest seller is I believe the Toyota Corolla. 'SUVs' (4WDs) have only recently boomed and peaked, and mostly for city wankers. Utes remain the vehicle of choice for practical farmers and tradesmen, with a special place in the hearts of bogans..

City planning is slightly better than the US, we're denser and have better public transport, but are still much closer to the average US city than European one. Maybe we're generally more like Boston than LA? Still plenty of roads and not enough trains.

Big country roads and distances however, which has been part of the reason for the popularity of the large car market.

In essence, I would suggest that we have a lot in common with the US, and high petrol prices (driven principally by tax rates) are the primary differential that has spurred us to have a more efficient vehicle fleet than the USA. And less (though still plenty) fuckwits driving their kiddiwinks in unsafe SUVs to school and the shops.
posted by wilful at 2:52 PM on December 16, 2008 [1 favorite]


I live in one Chicago suburb and work in another. There is no way for me to get to work via public transportation. The lack of density can't possibly justify the cost of putting in transport. For chrissakes, I pass horse farms on my way to work.

I know plenty of people in this position. Companies want to locate near a major city for the talent, but don't want to pay taxes or big-city rents for office space. It wouldn't be a big problem except a) crazy property markets and big transaction costs associated with changing neighborhoods b) couples with jobs in opposite directions.

I don't know what makes sense; density associated rents are pretty toxic.
posted by a robot made out of meat at 3:39 PM on December 16, 2008


But the stunt pulled on Top Gear tells us nothing useful.

Not entirely true. Driving continuously around a racetrack -- accelerating and braking -- will use the batteries somewhat, but even if they aren't, you're left with a car running around the track with a very small engine kept at full boil, versus a car of similar weight with a very large engine being kept at low revs.

So from this, we learn that how you drive is as important as what you drive, when it comes to mileage. I've seen this first-hand, driving my now-gone sports car at 3/10ths to keep up with traffic and getting 21mpg consistently, and driving my economy car at 7/10ths to keep up with traffic and getting 25mpg consistently on the same cycle -- you would have thought it would be significantly more, but it's not, because my economy car is underpowered for stop-n-go traffic.
posted by davejay at 12:58 PM on December 17, 2008


from this, we learn that how you drive is as important as what you drive, when it comes to mileage

which is exactly the point that Clarkson made at the end of that Top Gear segment.

I can also confirm this from experience. Ms flabdablet generally uses around 6 litres/100km in my car. I generally use around 5, even though I weigh much more than she does, because my driving style is smoother and less aggressive.
posted by flabdablet at 6:11 PM on December 17, 2008


« Older princess   |   Rhapsody in Glue Newer »


This thread has been archived and is closed to new comments