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Automotive News & Views Has CAFE reached the end of its usefulness?
507 messages, Last post on Oct 27, 2009 at 11:49 AM
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Replying to: li_sailor (May 15, 2007 8:12 am) |
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Replying to: li_sailor (May 15, 2007 7:47 am) What empirical evidence do you have to support this claim? Even you stated that mpg has decreased lately. Have CAFE standards been reduced? I don't think so but it certainly is true that the fleet's efficiency is less today than in 1987. I've asked this before. Why did the manufacturers ever exceed the standard? If the only reason they increased efficiency was to satisfy this mandate they never would have. It's not like they don't have absolute control over the composition of the cars they build. You've also stated that market forces are ineffective or less effective than CAFE. Then you've pointed out how places like Europe and Japan have nothing comparable to CAFE. Then why is it that their fleet's fuel efficiency is far higher than ours? In Europe it is partly attributable to the greater use of diesel but that definitely is not the case in Japan. Whether or not you understand the flaw in averaging mpg to determine a fleet's efficiency the fact is that with higher mileage hybrids and other technologies being developed everyone will eventually be forced to realize this as CAFE increases but the corresponding reduction in fuel consumption is not realized.
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Replying to: li_sailor (May 15, 2007 8:12 am) What does that mean? Do you consider this an intelligent rational for dismissing anything that is computed? Isn't CAFE computed? I defy you to do a websearch and find any reputable scientist or economist that considers average efficiency (mpg) to be as valid as average consumption (gpm). But you can't directly compare average mpg with average gpm. The average of 2 numbers do not equate to the average of their inverses. Yes gpm is the inverse of mpg. You're correct, average mpg will not equal the inverse of average gpm. If they did then it wouldn't matter whether you used mpg or gpm as your metric for measuring the fleet's efficiency. Have I not repeatedly stated that average gpm is a better method for determining fleet efficiency. The fact that I consider it better is a clear indication that I must also consider it to be different. So why are you pointing out to me that the two are not equitable? |
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Replying to: li_sailor (May 15, 2007 8:12 am) Actually I'm starting to wonder just how CAFE is computed. After doing some research they may very well be computing average gpm and then inverting it, which is how it should be. I've come across conflicting information, some stating that it uses average mpg, which of course is the wrong method. Does anyone definitively know the answer to this? Specifically, if an auto manufacturer sells one 10 mpg vehicle and one 40 mpg vehicle have they achieved a CAFE of 25 or 16? If it turns out that this results in a CAFE of 16 then they are, in fact, doing it correctly and basing it on average gpm.
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Replying to: tpe (May 15, 2007 9:29 am) I answered this before...they exceeded it by very little. And it's hardly surprising that they wouldn' tbe right on the mark given the indirect mechanism...basically marketing and price. If the only reason they increased efficiency was to satisfy this mandate they never would have. Again, there is nothing to support that conclusion, afaik. The fact that CAFE requirements and the fleet avg is so close is very unlikely to be coincidence. It's not like they don't have absolute control over the composition of the cars they build. But it is like they don't have absolute control over the sales. And that's what matters, not what they build. Then you've pointed out how places like Europe and Japan have nothing comparable to CAFE. Then why is it that their fleet's fuel efficiency is far higher than ours? You're kidding, right? Do you know the price of gas in Europe? In fact, this is a very strong case for why we need CAFE here in the US....because gas is so cheap here (relatively). You've also stated that market forces are ineffective or less effective than CAFE. The reason market forces are ineffective at forcing improvment in the current fleet is that gas price is based on the supply and demand of the oil produced without much regard for what will be able to be produced in the future. And also does not account for the political impact of the $. Those are the reasons we should improve the efficiency of our fleet and the market mostly ignores that. Whether or not you understand the flaw in averaging mpg to determine a fleet's efficiency... I understand your point. And the "flaw" is not re efficiency but rather in measuring consumption. The fact is that it's thoretical and as a practical matter, is pretty much irrelevant. I agree that CAFE should be re-cast (it is, in fact, being recast as we speak) to address the current condition. It will very likely be weight-based and possibly have other variations. There is no reason that we can't use a mpg-based system to set targets for various segments and be very effective at lowering consuption. Emprical evidence shows that CAFE did, in fact, lower consumption, per vehicle, over its initial period. |
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Replying to: tpe (May 15, 2007 10:52 am) total production ________________ model1 production/model1 mpg + model2 production/model2 mpg + model3 production/model3 mpg Using your example: 2 __________ 1/10 + 1/16 = 16 A link for the formula is here So after all this, it turns out that it's a moot point. But it was very entertaining and educational 
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Replying to: li_sailor (May 15, 2007 11:20 am) In 1980 the domestic fleet average was 24 mpg, CAFE was 20 mpg. I don't consider that to be very close. The fleet average for imports that year was 30 mpg, these cars were coming from countries that didn't have CAFE. But it is like they don't have absolute control over the sales. And that's what matters, not what they build. I suspect that the manufacturers typically sell every vehicle that they produce. If at the end of the year certain models aren't moving then discounts are offered. Ultimately your fleet sales average should be identical to what you produced. Empirical evidence shows that CAFE did, in fact, lower consumption, per vehicle, over its initial period. Empirical evidence only shows that per vehicle consumption declined over this period. It did not show that CAFE was the cause. CAFE will not change what people want to buy it will only change what they can buy. During this same, initial period people wanted to buy efficient vehicles. CAFE was a non-factor.
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Replying to: tpe (May 15, 2007 11:47 am) CAFE had barely started in '80. Afer '82 or so, CAFE and the fleet average have tracked pretty closely. The fleet average for imports that year was 30 mpg, these cars were coming from countries that didn't have CAFE. What relevance is that? Those vehicles were sold here, where there is CAFE. I suspect that the manufacturers typically sell every vehicle that they produce. Sure, but you think they don't adjust production to match demand over the course of the MY? We were talking about what they have more control over, production or sales. I think that's a no-brainer. During this same, initial period people wanted to buy efficient vehicles. CAFE was a non-factor. Not convincing. After the shock wore off and the incentive faded, efficiency remained at CAFE levels. It wasn't magic.
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Replying to: li_sailor (May 15, 2007 12:33 pm) The relevance is that these imported economy cars were developed and first adopted in countries that didn't have CAFE but were driven by market conditions. The consumer isn't required to comply with CAFE yet these vehicles that far exceeded CAFE standards became popular during this period. Why is that? You state that CAFE was in its infancy in 1980 but it had been 7 years since the first oil embargo and the fleet's efficiency had already almost doubled. Why is that? BTW, it's my understanding that the auto industry really didn't object too much to CAFE standards in 1975. Again, why is that? With gas above $3/gallon the feds probably could push through higher CAFE standards. Because just like in 1975 they are telling the auto makers to produce what the consumer wants. If the feds do this, in fairness to the auto industry, they better keep fuel at this price level or higher. Otherwise they are now telling a manufacturer to make something that its customers don't want. What will that accomplish? People will simply keep their existing vehicles much longer. The most efficient vehicle in the world doesn't do much good until it makes it's way into the fleet. |
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Replying to: li_sailor (May 15, 2007 12:33 pm)
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