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Transportation Science

Why Fuel Efficiency Advances Haven't Translated To Better Gas Mileage 891

greenrainbow tips an article about a research paper from an MIT economist that attempts to explain why technological advances in fuel efficiency haven't led to substantially better gas mileage for the average driver. Quoting: "Thus if Americans today were driving cars of the same size and power that were typical in 1980, the country’s fleet of autos would have jumped from an average of about 23 miles per gallon (mpg) to roughly 37 mpg, well above the current average of around 27 mpg. Instead, Knittel says, 'Most of that technological progress has gone into [compensating for] weight and horsepower.' ... Indeed, Knittel asserts, given consumer preferences in autos, larger changes in fleet-wide gas mileage will occur only when policies change, too. 'It’s the policymakers’ responsibility to create a structure that leads to these technologies being put toward fuel economy,' he says. Among environmental policy analysts, the notion of a surcharge on fuel is widely supported. 'I think 98 percent of economists would say that we need higher gas taxes,' Knittel says."
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Why Fuel Efficiency Advances Haven't Translated To Better Gas Mileage

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  • by Rifter13 ( 773076 ) on Friday January 06, 2012 @07:15PM (#38616058) Homepage

    The increase in gas prices hasn't drastically changed what vehicles we buy. Many of those that really would rather buy more efficient vehicles can't afford them, and are stuck with older ones, so the economists would just be hurting the poor.

    As consumers shouldn't we choose what vehicle economies we use? Where I live, SUVs are all over. But, it makes more sense. Adverse conditions favor SUVs. An economist, you would think, would say people buy what they want.

  • by Anonymous Coward on Friday January 06, 2012 @07:17PM (#38616084)

    The article links to the peer-reviewed, pay-walled version of the paper. the following is the version author put up on his website

  • So Tax Gas (Score:4, Informative)

    by alexander_686 ( 957440 ) on Friday January 06, 2012 @07:19PM (#38616110)

    If you want to reduce gas consumption (reduce oil imports, reduce green house gasses, etc.,) levy a carbon tax, don't increase gas mileage. Do it directly – not indirectly.

      Forcing me to pay extra to buy a fuel efficient car is going have little impact on the above issues – I don’t drive that many miles (yeah bike, mass transit).

    When the first MPG requirements were put in place, a lot of people switched from big gas guzzling station wagons to big gas guzzling light trucks – the minivan.

    Each year Americans drove more miles until gas hit $4.00 a gallon. Only at that point did they start switching their behavior. Smaller cars and shorter commutes.

  • Re:Statistics (Score:5, Informative)

    by DanTheStone ( 1212500 ) on Friday January 06, 2012 @07:23PM (#38616164)
    He should ask some economists. If we wanted to optional travel, gas taxes would help. But our whole nation's economy depends on motor vehicle travel to move goods. Raising gas taxes would significantly increase the cost of all goods and possibly bump us toward recession. It happens every time gas prices spike due to factors outside our control. So maybe the number of economists wouldn't be 98% after all.
  • Crash standards (Score:5, Informative)

    by Froobly ( 206960 ) on Friday January 06, 2012 @07:30PM (#38616264)
    While the SUV revolution is more than a little bit to blame for today's lackluster fuel numbers, the article fails to point out collision safety as a factor in the modern design of cars. It's not just the trucks and SUV's that are bringing the average down -- compact cars these days are still way heavier than they used to be, with much worse visibility, largely as a result of increasingly stringent crash standards.

    Cars these days have to be able to protect you in a 60 mph (30 + 30) corner collision, with rollover, even if you aren't wearing a seatbelt. The result is bigger, heavier frames, and thick pillars that prevent you from seeing pedestrians. As a result, cars are heavier, and their engines have to be more powerful to compensate.
  • Subaru Did It (Score:5, Informative)

    by bill_mcgonigle ( 4333 ) * on Friday January 06, 2012 @07:31PM (#38616270) Homepage Journal

    The 2012 Impreza gets 30% better [] gas mileage than the 2011.

    Read the article, but CVT, lighter body, electric steering - 36MPG for an AWD vehicle is nicely impressive.

    Technology, it does good things.

  • Re:Laissez faire (Score:2, Informative)

    by h4rr4r ( 612664 ) on Friday January 06, 2012 @07:34PM (#38616316)

    That would actually be one of the costs to interalize. Large vehicles kill drivers of smaller vehicles and as such should have to pay more.

  • Re:Statistics (Score:5, Informative)

    by hedwards ( 940851 ) on Friday January 06, 2012 @07:37PM (#38616364)

    This is a well known phenomenon and it's why you see such incredible fleet efficiency in Seattle compared with most of the rest of the country. Simply put between taxes and oil company gouging we pay more for our gas than they do in most of the rest of the country.

    It's been known since the 19th century: []

    Simply put if you don't tax the fuel sufficient to make up for the cost reduction you tend to get more fuel being consumed rather than less. There are limits to it, you're not going to suddenly start commuting 1000mi a day simply because of cheap gas, but it's less likely that you'll work close to home than if the gas was really expensive.

  • No incentive (Score:2, Informative)

    by Hentes ( 2461350 ) on Friday January 06, 2012 @07:42PM (#38616432)

    There were many advancements in fuel efficiency, but very few of them are actually used in American cars. American engines still have the simple design they had 40 years ago. With fuel prices kept low, there is just no incentive.

  • Re:Laissez faire (Score:4, Informative)

    by hedwards ( 940851 ) on Friday January 06, 2012 @07:42PM (#38616444)

    That's bunk. If you raise fuel costs it doesn't necessarily mean that the vehicles are going to be less safe. Safety is a separate function and is supposed to be dealt with before the vehicles are on the market.

    If you raise the price of gas the easiest ways of minimizing the cost are to either drive less or to drive slower and both of those are going to result in fewer fatalities. You don't magically remove safety features just because gas gets more expensive.

  • by Caerdwyn ( 829058 ) on Friday January 06, 2012 @07:42PM (#38616450) Journal

    What a load of tripe.

    The average weight of cars has been increasing because crash survival standards have been becoming stricter, and that requires that more material be used in the car to protect the passenger compartment. This adds weight and bulk; with bulk (thicker doors, etc.) comes an overall increase in vehicle sizes, which itself adds weight AND frontal area. The frontal area increase comes with an increase in drag. Exotic materials like carbon fiber are still very expensive, so it's still aluminum and steel. And despite what legislators seem to think, you can't pass a law that increases the number of joules of energy in a gram of fuel.

    It's not just American cars (so lose the anti-American screeching please). The average vehicle weight in ALL markets has been increasing. Go look up the dimensions and weights of just about any vehicle model and manufacturer regardless of market or whether the vehicle in question is sold in North America, and see how it's changed over time.

    Safety costs weight and size. Weight and size cost fuel. At a given price point, you can have increased safety XOR increased fuel economy.


  • Re:Laissez faire (Score:3, Informative)

    by h4rr4r ( 612664 ) on Friday January 06, 2012 @07:45PM (#38616482)

    The issue is they do not bear the costs. Larger cars kill those in smaller cars, they increase our need to go to war in oil rich areas and put out more pollution into the environment.

    The idea is to make them bear those costs and let them decide what is right for themselves. Right now they make these decisions based on a market that is not pricing these things in. Garbage in, Garbage out.

  • by sneakyimp ( 1161443 ) on Friday January 06, 2012 @07:46PM (#38616498)

    The super poor people I'm familiar with don't have cars. They take the bus or the subway.

  • Re:Statistics (Score:5, Informative)

    by ProfBooty ( 172603 ) on Friday January 06, 2012 @07:48PM (#38616516)

    The US gets most of its oil from canada and mexico. Since oil is a commodity, of course events in the middle east effect the price, even if the US doesn't actually obtain oil from those countries.

  • by lorenlal ( 164133 ) on Friday January 06, 2012 @08:11PM (#38616854)

    True enough... A lot of them think they can drive just like there's no snow, and others don't know how to drive in snow anyway.

    I live in one of those "not so friendly" areas. I also drive a car, front-wheel, with a diesel engine sitting right on top of the drive train. I handle snow very well, and better than some trucks and SUVs that I see... That or the drivers don't know how to handle what they've got.

  • by SoftwareArtist ( 1472499 ) on Friday January 06, 2012 @08:18PM (#38616928)

    Ok, take a deep breath. :) Relax. It's ok, really. Don't let your blood pressure go up like that. It's bad for your health!

    As lots of other people have been saying, a gas tax is not to punish you, it's to compensate for externalities. Every time you drive your car, you put wear on the roads and produce pollution. Those are real costs that people other than you have to bear. And since they are bearing those costs, not you, you have no incentive to reduce them by driving less or buying a smaller vehicle. You, in turn, are bearing the cost of other people's driving, and they have no incentive to drive less either. So that's why a gas tax is a good idea. Every time you (or I, or anyone else) drive, you should pay as close as possible to the actual cost of the damage you are doing. Then you can make more rational (in the economic sense) decisions about how much to drive and what car to buy. Your decisions will reflect realistic tradeoffs between various harms and benefits.

  • by dasunt ( 249686 ) on Friday January 06, 2012 @08:20PM (#38616952)

    I have 2 cars, a ford focus and a nissan xterra. the xterra is much better to drive in the snow. That doesn't mean i put it in 4wd and drive like a bat outta hell. It means i can just sort of plod along and never once has anything in the rockies, the midwest, or the northeast ever come close to stopping me. Compare that to the focus. It's front wheel drive. With all season tires, it's not a bad car for light snow, but it just doesn't have the ground clearance or wheel diameter to handle a significant amount of the stuff.

    I think you'd be surprised with what a great pair of winter tires will do on a little four-cylinder FWD car.

  • Safety is the reason (Score:4, Informative)

    by wmelnick ( 411371 ) on Friday January 06, 2012 @08:43PM (#38617186)
    But it is wrong. There are cars from the 1980s that get great gas mileage. The difference is the mandated changes for safety, which has made cars heavier. It takes more steel to make a car crumple the right way. I am not saying this is a bad thing - I am a fan of living through car crashes, but that is where the major mileage decrease happened.
  • Re:electronic junk (Score:2, Informative)

    by Anonymous Coward on Friday January 06, 2012 @08:56PM (#38617298)

    Simple car without all that junk == inexpensive car == low margins == little incentive to manufacture. Especially in the American automakers' case, when you factor in the large overhead of union retiree benefits per vehicle made. That's why Ford is luxxing out their previously lowly Focus and Fiesta lines.

  • Typical /. response (Score:5, Informative)

    by argStyopa ( 232550 ) on Friday January 06, 2012 @09:05PM (#38617386) Journal

    Gas prices are too let's raise taxes? That's our knee-jerk response?

    How about instead of raising taxes which will fall disproportionately on the middle class (the lower classes tend to use public transit), instead let's STOP subsidizing gas and oil exploration, remove massive subsidies, rebates, and all the frosting for our oil-lobby friends?

    Raising taxes on the masses while simultaneously handing $billion$ to oil means that the primary beneficiaries are the oil companies, nobody else.

  • by hawguy ( 1600213 ) on Friday January 06, 2012 @09:15PM (#38617502)

    Your telling me that winter tires are not mandatory in wintery states in the US?! No wonder there are all kinds of crazy when a snow storm pops by. Here in Norway your required to have winter tires on after a specific date, and they need to have a minimum thread depth.

    Nope, not mandatory at all in most areas, but I can't speak for the entire country. I've been on some mountain roads in California where they make sure you have at least all-season tires that are M+S (mud and snow) rated or they require snow chains, but all season tires are a poor substitute for quality winter tires. But I think the all kinds of crazy that happens during a winter storm is more due to poor driver skills than the tires they have on their cars - many people don't understand that just because their car will accelerate to 50km/hour on a snow covered city street, that doesn't mean that they will be able to negotiate the curve ahead at that same speed without sliding off the road.

    Not even our northern-most state of Alaska requires snow tires in the winter: []

  • Re:Statistics (Score:5, Informative)

    by sneakyimp ( 1161443 ) on Friday January 06, 2012 @09:17PM (#38617522)

    The link you provided cites as it source the EIA which is the very site that I linked in my post. I'm not sure what you're trying to say. Nickel-and-dime me all you like, the story is still gloomy. Here's more []. The US consumes 20 million barrels of oil per day -- almost a quarter of the world total. We spend roughly $522B each year on petroleum. More than half of our petroleum (58%) is imported. We send about $300B abroad each year to support this nasty habit. And the price is volatile! If the price per barrel stays at its current value which is over $100 per bbl [], then we will be spending $700B and sending $400B abroad every year. That's a lot of treasure -- and I haven't factored in any costs for our wars which are arguably caused by our desire to insure oil supplies. Personally, I would like to see that $400B spent here at home.

    As for my original point -- that we are sending a lot of money to some dodgy regimes -- here is some more detail. We import 5 million barrels per day from OPEC. We import 1.465 million barrels per day from Saudi Arabia alone. The average cost per barrel for crude oil is $74.71 per barrel. *Every single day*, that comes out to:
    $109,450,150 USD to Saudi Arabia ($40B/yr)
    $56,704,890 USD to Venezuela ($21B/yr)
    $39,521,590 to Nigeria ($14B/yr)
    $30,108,130 to Iraq ($11B/yr)
    Iran - none (my bad).

    That paltry 16% of our oil imports from the Persian Gulf means we are sending $48B (16% of imports which are 58% of total 522B) to the Persian Gulf every year.

  • by Anonymous Coward on Friday January 06, 2012 @09:23PM (#38617584)

    Citation please? Do you have any data for how much of the weight increase is caused by safety features?

    Try this: In 1980 I purchased a new VW Rabbit C. Curb weight about 1650 lbs. About 23 in the city and 36 highway.
    In 1999 I purchased a new VW Jetta. Curb weight about 2350 lbs. About 23 in the city and 32 highway. Why the big weight increase?
    Mostly safety systems - required stiffeners in the unibody, anti-intrusion beams, rollover requirements, multiple air bags, heavier structure.
    Add to that a statement from the govt. agencies that the "ideal" vehicle weight was 2400 lbs...

  • Re:Statistics (Score:5, Informative)

    by thejaq ( 2495514 ) on Friday January 06, 2012 @09:32PM (#38617666)
    What odd behavior. YTD 2011 50% of oil is domestic and the two largest imports come from canada and mexico (~18%). Furthermore only about ~10% comes from the middle east, the balance is africa and s. america. So apart from your priggish "correction" he remains correct in his main point.
  • Re:Laissez faire (Score:4, Informative)

    by ChrisMaple ( 607946 ) on Friday January 06, 2012 @09:59PM (#38617914)
    The proper role of government is to protect the rights of its citizens and nothing else. A representative democracy is only a mechanism to attempt to have a government act in that manner. Thus it is not the politicians who should be making those choices, usurping the decisions of individuals.
  • by errhuman ( 2226852 ) on Friday January 06, 2012 @10:20PM (#38618120)
    So don't drive on to the wedge of snow?
  • by tkrotchko ( 124118 ) on Friday January 06, 2012 @10:27PM (#38618178) Homepage

    You've nailed it exactly.

    Cars weight a lot more than they used to. My 1981 Honda civic weighed 1,700 pounds. It got by with a 1.5l 67 HP motor. I got 35 MPG around town, 50 MPG on the highway

    By contrast, a 2012 weighs 2600 pounds, and has a 140 HP motor. It gets 28/39 MPG.

    The 2012 is by every measure a better car. But it gets significantly poorer gas mileage.

    The new Civic I'm sure is safer

  • by ChrisMaple ( 607946 ) on Friday January 06, 2012 @10:43PM (#38618310)

    The oil depletion allowance is not "subsidies for the oil industry", it's a perfectly just compensation for a declining asset.

    the "impulse" to use the physics term is actually greater for two heavier vehicles colliding, thus harming both occupants more. Two light-weight vehicles would be the safest to collide

    That's just silly. The crash energy is absorbed in collapsing structures located between the front of the vehicle and the passenger compartment. Those structures are designed in proportion to the vehicle's weight, among other things. As I indicated in a post above, greater distance between the front and the passenger increases safety. A bigger crumple zone reduces deceleration and allows more room for a variety of protections for the passenger.

  • by Demonoid-Penguin ( 1669014 ) on Saturday January 07, 2012 @10:33AM (#38621234) Homepage

    It's always been cheaper to eat good food than to buy junk food.

    Not where I'm at in the Great Lakes area about halfway between Detroit and Chicago. Fresh produce and the healthier alternatives typically sell for a premium price. It's fairly standard supermarket/food industry practice to charge a premium price for items that carry what they consider to be marketing buzz-words to be monetized. Anything that can be labeled with (or could be said to naturally be) "fresh", "organic", "low fat", "all natural", "diet", "sugar free", "low cholesterol", "low sodium", etc etc always costs more than the less-"healthy" alternatives.

    At typical food prices in this area and with what a poor person receives in food stamps, it's a struggle to simply get enough calories of any kind to last them all month. Eating a healthy diet as recommended by the FLOTUS and others would mean that this poor person would probably run out of food somewhere around the end of the third week of the month, maybe sooner. Either that, or be undernourished to some degree all month.

    That's the reality many face; do they choose to eat unhealthy or go without eating some days, or not eat enough any day.


    It's always been cheaper to eat good food than to buy junk food.

    Not where I'm at in the Great Lakes area about halfway between Detroit and Chicago. Fresh produce and the healthier alternatives typically sell for a premium price.

    I wasn't referring to "organic" or "premium foods". That's part of the problem - people are either too picky or just can't cook.

    Cheap pasta, dried beans, rice, tinned tomatoes, onions, rolled oats, sultanas, desiccated coconut, flour, drum of olive oil, a cheap loaf of french or italian "home" style bread unsliced. Those things are cheap. Everywhere, all year round. Add in whatever is cheap in season - carrots? celery? cabbage? potatoes? How about some cheap canned tuna? some eggs (to be used with the flour), maybe a bit of rump steak and some kidneys if you're a meat eater (but not every meal, or as the majority of a meal), throw in a packet of tea (not bags) or coffee (cheapest vacuum packed - *not* instant). A few spices - food doesn't have to be boring - pepper, cinnamon, chilli, cheap minced garlic. All those things can be bought once a week - no need to spend hours shopping every days.

    A kilo of block of cheap cheese stretched over a couple of weeks. Notice I didn't put sugar, milk, or chocolate on the list - except for bread everything has only one ingredient. (quantities are per person)

    People are dumb, and lazy - both handicaps can be overcome *if* they want. Those ingredients will supply the more vitamins than junkfood - without missing out on the required *protein* (not calories - that comes later)

    Sure - people who are used to high salt, fat, and sugar foods will not find it interesting - easy fixed. Go to bed hungry. Hunger is the best sauce.

    But people go from one extreme to another - they either eat junk food which is not cheap - or they buy premium "health" food. Most of which goes to waste. The bigger the fridge - the more waste.

    An apple a day is nice, maybe a banana. But even if you only eat a plum or an apple a week you're better off than if you ate one of those choko/apple things from Maccas every day. Rolled oats with some sultanas and coconut - soak for ten minutes in boiling water - add some milk and it's breakfast.

    People watch all those fucking gourmet cooking shows when all that's needed is simple things - doesn't mean they can't taste nice. And most everyone can find somewhere to grow a few herbs - bit of parsley, some basil. Why does it have to be either Pizza Hut and Pepsi Colonic or snowpea and mango salad? It's nice to have fresh tomatoes - but it's hard to justify the cost when it's not the local season - and they've got fuck all heath benefits when they've been trucked/flown 2000 miles. And orange ju

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