Comments needed on draft response to AAA press release

Discussion in 'Website news & discussions' started by lightfoot, Jun 29, 2008.

  1. laurieaw

    laurieaw Sorceress of the North

    in other words, and correct me if i am reading this wrong, if they are speeding on a road on which the drivers figure the limit is too slow, so they speed, AAA wants them to not put a speed trap there? is that what this says? in other words, ignore the limit and don't pick them up, because it looks like the road should have a higher limit. doesn't that seem to apply to just about any road in the country lately?
     
  2. Nikki

    Nikki Well-Known Member

    I thought about that after I hit "send." If I lived in a small town, I'd want folks to slow down from the 55mph PSL on a 2 lane highway in a rural area to a more reasonable 35-40 mph in town. Slower speeds in town would make is safer for me, my children, and my pets, if any of us make a mistake & step out into the street.
     
  3. laurieaw

    laurieaw Sorceress of the North

    i totally agree. the comment made by AAA makes it sound like since some drivers think that in an engineering sense, this road could handle higher speeds, and therefore they do it, that it would be overlooked as far as catching speeders.
     
  4. lightfoot

    lightfoot Reformed speeder

    On thinking about this, I agree that the SAE test is inconclusive, except in the sense that for radials it did NOT find evidence of loss of grip, uneven wear, or reduced tread life at the max rated tire pressure. So I'd just delete mention of it, or at most refer to it and say that it "suggested" these things. The bruising issue is somewhat unclear, for reasons I'll note elsewhere..

    As for the sidewall rating, that is a specification printed on the side of the tire. It's not a recommendation but it is the upper limit specified by the tire mfr.

    revision:

    "Inflating tires. The AAA incorrectly calls it “over inflating” when tires are put at the maximum pressure recommended on the sidewalls by the tire manufacturer. This is within specification, not “over”, and in any case a safety margin is built into the tire manufacturer’s rating. Inflating to the sidewall rating is recommended by some police officers for their own cruisers for improved wet and dry grip ( http://www.officer.com/web/online/Editorial-and-Features/Driving-Under-Pressure/19$27281 )."
     
    Last edited: Jul 1, 2008
  5. lightfoot

    lightfoot Reformed speeder

    The reference is to what was done, not to what was not done. Scientifically yes pointing out a reference's shortcomings in a citation in a research paper would be normal, but this simply states that the study did not find any loss of grip.

    Yes, the statement in the draft was wrong.

    This whole test has problems for me, and I'm just a biologist:

    (1) Relevance: Is there any evidence that data from this test will have relevance to the range of obstacles a tire may encounter in normal use: potholes, curbs, thrown tire treads? In essence it replicates what might happen if one hit a bit of rebar sticking up from the street. The other tests they did appear at least to me to have some relevance to normal use, though as you point out the grip test does not mimic a bumpy road (how bumpy is another question!).

    (2) The ordinate seems to be in terms of energy, so what is the raw data for height? If the 30% applies to a height of 1", the difference is only 1/3". If the 30% applies to a height of 3", the difference is 1". Finding a projection 4" high seems like a rare event? And either way, it's only the 30% one is concerned about: shorter projections would not affect the tire at either pressure and the 30% higher ones would burst it either way, right?

    (3) So what happens if you're at max load and therefore need to use a pressure somewhere near the sidewall rating (I think you said that the pressure to be used at max load was a bit less than the sidewall rating?). Apparently this means that the tire would be more likely to bruise? (I would suspect that in addition to the increased pressure, the greater load on the tire would make it even more susceptible to bruising, but maybe I'm wrong?) Anyhow, presumably this greater risk of bruising at this near-max-sidewall-pressure required by the max load rating is acceptable? Or does the risk of bruising make the pressure required for max load unacceptably risky so one shouldn't carry the max load?

    What this seems to indicate is that the 30-50% increase is scientifically meaningful in this test but is a small factor in comparison to the variations in the real world. In other words, reality is too complicated for science to describe completely, which I run up against all the time.

    Out of curiosity, is there any evidence that repeated impacts cause a cumulative weakening of the tire?
     
  6. fixedintime

    fixedintime Well-Known Member

    Something to keep in mind in these discussions is that in today's legal climate no tire company is going to put a maximum pressure number on a tire if they think that in any way it is unsafe to inflate a tire to that pressure. They may be required to put a number there, but no one says what the number has to be.
     
  7. gershon

    gershon Well-Known Member

    I'd suggest we take up a collection and put it on a newswire. I'd be willing to give $50.

    AAA won't pay any attention to us here. If it's pointed out that their statements are false and misleading in the newspapers nationwide, we will see quite a bit of backpedaling.
     
  8. Chuck

    Chuck just the messenger

    I'll second that.
     
  9. Steve_O

    Steve_O Active Member

    "(3) Drafting – cleanmpg specifically recommends against drafting on safety grounds alone. In addition, it is more efficient to slow down than it is to draft a semi at typical truck speeds. The AAA’s accusation is especially perplexing because drafting is basically tailgating."


    Please don't take this as an insult but, isn't it curious that many of the people posting about AAA (for example: xcel, right lane cruiser, lightfoot, and deltaflyer) have self-admittedly practiced close-in drafting, as designated with the letter "L" in the mileage logs.
     
  10. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Steve O:

    ___So have you and everyone else that has traveled even 15 miles on a crowded Interstate. I am just not afraid to say when someone pulls in front of me while I am at the speed limit that I am suddenly way to close and nowhere near a 2-second interval. All you have to do is count the seconds and you will see what is really going on. I saw maybe 10,000 Close-in’s in the left lanes on my way to O’Hare and back today and that is because I only saw 10,000 cars that were traveling near enough to me to notice. I was only in maybe 20 as the speed demons cut in front way to close :(

    ___Good Luck

    ___Wayne
     
  11. Steve_O

    Steve_O Active Member


    I wholeheartedly agree, and also thanks for not ripping me a new one in your reply.

    So then by designating that close-in drafting was used as a technique, does that mean that it was unintentional? To put this another way: do you guys back off if someone pulls in too close in front of you? In uber-heavy traffic, is backing off a futile response due to other autos merging into your gap?

    PS: I pulled 28.5 mpg in the city today, 27.9 in the city yesterday, and 29.5 on the highway the day before. That is an increase of 154%, 151%, and 160% respectively of the new combined EPA value!
    :woot:
    I owe it all to you guys. Thanks!
     
    Last edited: Jul 2, 2008
  12. lightfoot

    lightfoot Reformed speeder

    Huh? I wasn't aware that I had entered that but if I did it was a mistake. I have NEVER close-drafted with the Insight. It's an instant classic so there's no way I want stone nicks on the front end.

    I don't log the Subaru, but I did close-in the Subaru once for 20 miles as a test to see what the mpg was.
     
  13. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    Steve, I second Wayne's statement. I do not look for close in drafting but I have no choice when someone cuts in front of me on the highway with less than 3' of clearance. Until that person pulls away from me, I'm in a close in draft through no fault or effort of my own. I have included it in the logs in an attempt to be complete about all effects on my driving during a tank -- I've stated this more than once in the past.

    I don't seek close in drafting (actually, I don't even seek long distance drafting because that is too fast as well) but I end up participating because of dangerous and illegal passing tactics of other drivers. This is regrettable and unavoidable.

    By the way, you are perfectly right to ask about this -- it is relevant and important.

    And yes, it is somewhat futile to try backing off on the highway because of the volume of traffic... though the proper combination of positioning and speeds will often encourage others to change lanes well before reaching me. This promotes a higher speed pass and often makes cutting too close to me all but impossible. I will say that if I have any control at all I'm never closer than 3 seconds from the vehicle in front of me.
     
  14. hobbit

    hobbit He who posts articles

    This all strikes me as odd, since the New England AAA branch
    seems to have been mostly sensible over the years and one of their
    columns is from a MA state police sergeant over in Danvers on a
    variety of traffic safety topics. I actually called him up one
    day to offer positive feedback on what he was doing, and he was
    really pleased with that. I probably went on at him about the
    tailgating thing, it was a while ago.
    .
    Some of the stuff that comes through AAA national could be
    better, though, like John Paul's vehicle reviews that seem
    to frequently employ aggressiveness and speed-n-power as
    positive features ... although almost every vehicle thus
    described also carries "fuel economy" as one of its thumbs-
    down points. Mostly the mag is essentially ads for travel
    destinations and other fluff.
    .
    I'd really like to see them take a stand on the following-
    distance thing, though. THREE seconds minimum. It works
    just fine in urban environments -- I always get this non-starter
    counterargument from people I advocate this to about how someone
    will jump into the gap and cut me off, etc etc -- which I
    consistently answer [and practice] with "make the gap
    bigger, and then it doesn't matter and helps surrounding
    traffic". Works for me.
    .
    _H*
     
  15. CapriRacer

    CapriRacer Well-Known Member

    I've been thinking about this, too.

    First, I went back and re-read the news release. It is obvious that this news release is directed towards the average motorist - and while single out "hypermiling", I don't really think they are singling out "hypermilers" as a group, just some of the techinques to achieve better fuel economy - AND, in particular techniques that have safety consequences that may be unknown to the average motorist.

    Since my area of expertise is tires, I'll confine my comments to that area, but I think - as a whole - it is applicable to the entire release.

    The news release doesn't specify what is meant by "overinflation". Everything that is mentioned is "conventional wisdom" within the tire industry - all of which may be true if enough inflation pressure is added to a tire. None of what they say is patently false, given that the pressure range is not specified.

    Overall, the inflation pressure portion of the release is a good warning to folks who have no knowledge about tires - and tire pressures - and in the absence of guidance, may inflate their tires to a level that becomes dangerous.
     
  16. Ophbalance

    Ophbalance Administrator Staff Member

    But really, where is dangerous? To be honest, I've not really seen you offer up much of any evidence other than that SAE paper, both here and on ecomodder.com. I realize that one of us, or even all of the members here are a statistically small amount, but I've never heard a single person here that has had a tire blow due to inflating to the stamped amount on the tire. Nor have I heard anyone say, "geeze man, I completely lost control through that turn".

    To be frank, I expected you (a tire expert) to come up with much more compelling information and expertise both here an on ecomodder. In my view, you've fallen short on both accounts. One SAE paper does not a compelling argument make.
     
  17. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi CapriRacer

    ___I know that max-sidewall and above increases tire longevity, reduces hydroplaning, allows more even wear across the tread over the life of the tire and improves FE. The AAA is bringing the contact patch in without also adding the increased friction within the patch due to the same weight distributed over that same contact patch.

    ___What is not being output are those facts.

    ___Good Luck

    ___Wayne
     
  18. gershon

    gershon Well-Known Member

    Wayne,

    Maybe it will help to remember that all this "wisdom" was spewed out by a reporter who by her on admission just learned how to check her tire pressure on the day of the video.

    Gershon
     
  19. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Gershon:

    ___Very good point …

    ___I am formulating a plan to help the new Hypermilers come into the fold with less transition about safe and legal vs. the garbage the AAA has put out. If gasoline continues to rise, this country is going to go nuts and the last thing I would want to see is someone in an Excursion pull into a FAS without understating its ramifications and actually causing mayhem let alone they should not have been driving the behemoth in the first place.

    ___Just following the speed limits with the basics and a well setup vehicle is worth so much more than what the AAA and others have offered and here we are defending what seems like common sense safety practices while the media spins in whatever direction the breeze is blowing that day?

    ___Good Luck

    ___Wayne
     
  20. fixedintime

    fixedintime Well-Known Member

    One change I would make on this site to improve credibility and to be more professional is to delete anything from the mileage logs that is illegal.

    So I would not even have close in draft on the list as a choice. We would not put on running stop signs - it saves gas, or running traffic lights - it can save gas as well.

    In that same vein I would check and see if any state says it is legal to coast in neutral. If every state said no, even people here disagree with that position delete it. We don't say it is ok to do 55 in a 45 mph zone to save gas because it is illegal. If every state says coasting in neutral or with the engine off in a ICE is illegal so be it. If we don't like it we can argue to have it changed. But in the meantime it remains illegal.
     

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