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    MIT Professor Says Weight & HP Kill Gains In Efficiency


    William Maley

    Editor/Reporter - CheersandGears.com

    January 4, 2012

    It's not any news that cars are getting heavier by the moment due to new safety reguations and luxuries like power windows and sound proofing. A new report shows how both have been detrimental to fuel economy gains.

    Christopher Knittel, a professor of applied economics at the M.I.T. Sloan School of Management published a paper in the American Economic Review stating that if weight, horsepower, and torque were held to levels in the 1980s and fuel efficiency techologies were improved, fuel economy for cars and light trucks could see an increase of by almost 60 percent from 1980 to 2006.

    In a interview with the New York Times, Knittel said the biggest contributor to the weight gain is due to consumers changing preferences.

    “In 1980, just 18 percent of new cars sold in the United States were light trucks. By 2004, it was 60 percent. That led to a 30 percent increase in weight over that time, and a doubling of horsepower.”

    Not surprisingly, the auto industry isn't taking too kindly to Knittel's report.

    “This year, automakers are selling 270 models that achieve 30 m.p.g. or more. The M.I.T. report stops at 2006, just when automakers began meeting greater consumer demand for fuel economy with new technologies. In 2008, when gas reached $4 a gallon, we couldn’t keep the most fuel-efficient autos on dealers’ lots,” said Gloria Bergquist, a spokeswoman for the Alliance of Automobile Manufacturers in a email.

    Knittel acknowledged that gasoline costing $4 a gallon in 2008 led many buyers toward fuel-efficient vehicles and away from SUVs and pickups, but it wasn't indicative of an unstoppable trend.

    "They certainly were losing weight then, but as gas prices fell that shift has slowed. I’m not faulting the automakers. It’s the role of policymakers to incentivize fuel economy shifts,”

    So what does Knittel think should happen? Knittel favors a gas tax than the new CAFE standards.

    “Performance standards like CAFE are highly inefficient, but they’re politically palatable,” he said.

    Source: New York Times

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    Aside from the comments above, our enlightened scientist misses many points:

    Christopher Knittel...published a paper...stating that if weight, horsepower, and torque were held to levels in the 1980s and fuel efficiency techologies were improved, fuel economy for cars and light trucks could see an increase of by almost 60 percent from 1980 to 2006.

    Horsepower of a mid-sized car in 1984 was under 150hp, 0-60 time was just under 10 seconds, cars had no modern safety equipment (airbags, ABS, traction control, etc), and they were relatively uncultured (loud, rough, etc).

    In a interview with the New York Times, Knittel said the biggest contributor to the weight gain is due to consumers changing preferences...“In 1980, just 18 percent of new cars sold in the United States were light trucks. By 2004, it was 60 percent. That led to a 30 percent increase in weight over that time, and a doubling of horsepower.”

    The switch from cars to trucks was mainly due to the public's desire for larger, heavier vehicles as car's got lighter and smaller. While the shift to SUVs did increase the weight of the average new vehicle, the addition of civilizing characteristics (safety, sound deadening, improved suspensions) contributed quite a bit as well. And the "doubling of horsepower" is directly related to improved engineering and not the shift to truck-based vehicles (which, typically didn't have much more power than their car-based counterparts).

    Along with our safer and more pleasant vehicles, they're much more efficient. A Ferrari 30 years ago just topped 200hp, now family cars far exceed that...and get double the gas mileage at the same time. Manufacturers are shifting toward even more efficent engines since front-drive cars can't handle more than 300hp. With V6 engines easily topping that number, cars are now coming with smaller engines putting out high power...noted by the shift toward four-cylinder engines replacing V6s in larger and larger vehicles.

    So what does Knittel think should happen? Knittel favors a gas tax than the new CAFE standards.

    Most economists will agree with this. But how many politicians will vote for more taxes?

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    Horsepower of a mid-sized car in 1984 was under 150hp, 0-60 time was just under 10 seconds, cars had no modern safety equipment (airbags, ABS, traction control, etc), and they were relatively uncultured (loud, rough, etc).

    30 years later, it is easy to call these cars loud and rough... but one is judging from a viewpoint polluted by 20 years of these cars rattling around in decline and tainted by cars today that are so stealthy quiet that they are dangerous to blind pedestrians and stupid drivers whom are unclear if the car is running or not.

    Many 1984 cars were quite quiet and smooth when new or well maintained, but you can't expect that from low end offering, such as a Chevette.

    Not only that but some of us feel 1984 cars had all the safety equipment needed... some chrome bumpers to guard the car when parked and a decent, attentive driver when it was moving. I have yet to pop an airbag or trigger the ABS or TC in such a way that I would say 'saved me from an accident'.

    (which, typically didn't have much more power than their car-based counterparts).

    Size, dwindling engine choice and the sudden switch to FWD between 1980 and 1988 is when the trucks really started to get a head of steam and the manufacturers responded by 'civilizing' trucks. Once most trucks had the comfort options cars used to have, the truck trend spiked.

    It is quite true that trucks didn't have a lot of hp more than cars, they had enough. The difference between a 305 and a 350 is quite noticable, and with few exceptions, GM flat out refused to put a 350 in ANY car between 1980 and 1990, even though it was easy done by a shade tree mechanic with neglibile loss of economy or increase of emissions.

    Also, we talk of horsepower, but what really people feel when the car accelerates is torque. And trucks could still be optioned with higher torque 454 engines.

    Most economists will agree with this. But how many politicians will vote for more taxes?

    Well, its fine if the gas taxes are used to build roads... but they usually aren't.

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    30 years later, it is easy to call these cars loud and rough... but one is judging from a viewpoint polluted by 20 years of these cars rattling around in decline and tainted by cars today that are so stealthy quiet that they are dangerous to blind pedestrians and stupid drivers whom are unclear if the car is running or not.

    Yes, there were cars that were quiet, but compare an entry-level or family car then and now and you'll see the VAST improvement in nearly every measurement. Compare that Chevette to a Sonic (the Cruze would just embarass the Chevette) and see.

    Not only that but some of us feel 1984 cars had all the safety equipment needed... some chrome bumpers to guard the car when parked and a decent, attentive driver when it was moving. I have yet to pop an airbag or trigger the ABS or TC in such a way that I would say 'saved me from an accident'.

    You can't have it both ways. Stupid drivers need to be protected from quiet cars, but having them die in less-than-modern cars is okay? You're not going to pop an airbag at parking lot speeds and ABS typically doesn't work travelling really slow either. Some of us feel that 1984 cars didn't have enough compared to what's available today. MANY modern drivers NEED these things. Traffic injury stats prove this out.

    Size, dwindling engine choice and the sudden switch to FWD between 1980 and 1988 is when the trucks really started to get a head of steam and the manufacturers responded by 'civilizing' trucks. Once most trucks had the comfort options cars used to have, the truck trend spiked.

    The former point was caused by CAFE. The latter point was the result of demand for vehicles basically prohibited by CAFE.

    Also, we talk of horsepower, but what really people feel when the car accelerates is torque. And trucks could still be optioned with higher torque 454 engines.

    Today's vehicles are considerably quicker than those of 30 years ago.

    Well, its fine if the gas taxes are used to build roads... but they usually aren't.

    Actually, the need to get people to buy more reasonable vehicles is the point, not road repair. I, for one, would like to see all highway monies earmarked exclusively for travel-related costs...mass transit, road repair, etc. But the real point is to get single drivers out of large vehicle that they have no real need to be driving...like they have done in Europe. I don't want $8/gallon gas, but I also don't drive a gas guzzling truck to commute back and forth to work...as many people do.

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    Yes, there were cars that were quiet, but compare an entry-level or family car then and now and you'll see the VAST improvement in nearly every measurement. Compare that Chevette to a Sonic (the Cruze would just embarass the Chevette) and see.

    Actually, the Sonic might be quieter, safer and faster than the Chevette... but I cannot physically fit in a Sonic, so its useless to me. I've driven Chevettes... but they were coupes. I also put a giant 25" console TV in the back of a Chevette.

    You can't have it both ways. Stupid drivers need to be protected from quiet cars, but having them die in less-than-modern cars is okay? You're not going to pop an airbag at parking lot speeds and ABS typically doesn't work travelling really slow either. Some of us feel that 1984 cars didn't have enough compared to what's available today. MANY modern drivers NEED these things. Traffic injury stats prove this out.

    I believe in Darwinism. Fewer stupid people helps the species. When does the safety stop... do you wish to be bubblewrapped before you exit the house? The question of automotive safety comes down this... don't allow anybody to move faster than a walking pace. That will be the safety that our public NEEDS if the driving skills continue to plummet.

    The former point was caused by CAFE. The latter point was the result of demand for vehicles basically prohibited by CAFE.

    Of course it was caused by CAFE. The rule of unintentional consequences rendered large cars functionally obsolete, but it didn't need to be that way. With the new CAFE rules, I'm waiting to see semi-based SUVs with 25,999 GVWRs and more...

    I have driven fullsize cars that are lighter than the current Malibu, and nearly as economical.

    Today's vehicles are considerably quicker than those of 30 years ago.

    You wouldn't know it the way people drive. I see garbage trucks out accelerate some of the clueless out there.

    Of course, in our household, our cars all seemed to have balls... and could get from 0-60 as fast at the '04 GP GTP does... but you didn't have to fight the TC on the RWD cars we had. Sure, the GTP will outrun most of our past cars... but I'm not interesting in going fast from 60-100.

    Actually, the need to get people to buy more reasonable vehicles is the point, not road repair. I, for one, would like to see all highway monies earmarked exclusively for travel-related costs...mass transit, road repair, etc. But the real point is to get single drivers out of large vehicle that they have no real need to be driving...like they have done in Europe. I don't want $8/gallon gas, but I also don't drive a gas guzzling truck to commute back and forth to work...as many people do.

    What good does getting people to buy more reasonable vehicles if the roads are so bad you have to replace it every few years? Studies have shown that our roads are costing us a fortune in wear and tear on our cars. Everyone thinks they are so green to drive a Prius, but the energy used and pollution created in making one car is VAST. One study I remember from a decade ago found that replacing the worst gas guzzling, polluting mess of a car off the road with one new economy car created MORE pollution and used more energy than just keeping the old guzzer running nonstop for 50 years.

    Some people seem to have this idea of a utopian paradise were everyone is riding around in little Smart cars... its just not going to happen. Some of us need a larger (or largest) car. But nobody makes large cars anymore... so I guess my next purchase will have to be a huge, top heavy truck. Blah.

    Make the gas tax too high (or use the proceeds for unrelated BS), and people who need big vehicles will start using woodgas again. That ain't going to help the forests one bit.

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    I may only get 14mpg out of my Toronado (needing a carb tuneup I believe) but it still used less energy than if I bought a brand new car, especially seeing as I only do about 4,000 miles a year in it.

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