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Post by WebDragon on Dec 29, 2012 6:42:59 GMT
isn't it the observer inside the truck who has the most vested interest? ;D ...and likely the observer from the vehicle in front of it. I think this would be a decent show idea because there are many misconceptions and somewhat counter-intuitive notions, for the general public. We've obviously got knowledgeable participants on the topic here, but discussing the outcomes and touting experience doesn't get it on the show. It's a great idea and we've got qualified experts here. The next step is to propose a collaborative DoE (Design of Experiments) to the producer(s)... and as I understand, cyber' has provided that avenue. I'll offer the following as a start: _______________________________________________________
SCOPE: To test the straight line stopping distance of various road going vehicles.
SUBJECTS: 2 wheel, 4 wheel and Multi wheel transport vehicles.
TEST: The subjects are brought up to common traveling speeds* on US roads and then "emergency" stopped to zero speed. *Suggested speeds: -30mph (50km/h) -50mph (80km/h) -70mph (112km/h)
ASSUMPTIONS: - vehicles are fit to travel per US transportation regulations. - vehicles are laded per US transportation regulations. - vehicles are tested on the same road surface. - vehicles are tested at the same temperature, humidity and dewpoint. - braking is applied at maximum, non-skid force. (in the case of multi-wheeled vehicles, momentary skidding of non-drive wheels should be noted). - ?
VARIABLES: - Gross vehicle weight unladen - Gross vehicle weight laden - Center of Mass unladen - Center of Mass laden - Aggregate contact patch - ?
ERROR POTENTIAL - non-conformance to *assumptions - accuracy of data collection. - speed control. - (N)umber of vehicles available. - (N)umber of trials available. - statistical mis-evaluation due to limited (N). - statistical mis-evaluation due to non-observance of *assumptions. - statistical mis-evaluation due to limited understanding of statistics. - ? _______________________________________________________The above is just the beginnings of a development plan, please "quote it" and contribute as needed. As we all know, the MBs like to ramp it up!, unsecured loads, stray obstacles, C4 or Cruise missles can all play into making this episode more palatable to their demographic. Feel free to add the ridiculous beyond the reasonable, which demonstrates scale.
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Post by the light works on Dec 29, 2012 11:51:10 GMT
I'm going to add "dynamite the brakes" stop to the tests as well because if it isn't done, there will be complaining.
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Post by srmarti on Dec 29, 2012 21:21:02 GMT
How are you going to assure the driver safety testing what an unsecured load does?
Going to make it a remote control truck or tow it at a test facility?
Not too interested in seeing them duplicate crash tests. The real thing is no doubt available on line and real crashes are on the new frequently enough.
I'm not a fan of gratuitous explosions, granted many fans are.
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Post by the light works on Dec 29, 2012 23:51:24 GMT
How are you going to assure the driver safety testing what an unsecured load does? Going to make it a remote control truck or tow it at a test facility? Not too interested in seeing them duplicate crash tests. The real thing is no doubt available on line and real crashes are on the new frequently enough. I'm not a fan of gratuitous explosions, granted many fans are. what part of" - vehicles are fit to travel per US transportation regulations. - vehicles are laded per US transportation regulations. implies an unsecured load, to you?
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Post by silverdragon on Dec 30, 2012 7:06:23 GMT
I think an important part of the test would be what happens when you dont. This from the discussion on previous pages, it CAN be done wrong, and obviously is on a daily basis. TLW, Smarti has a valid point, sometimes you only find out a load isnt secure when it comes loose?.... I think its important to test a load put in place by someone who thinks its loaded right, against a load thats loaded by someone such as one of my many fellow drivers the world over who is seasoned and has experience... Case in point, my Son bought a new bike, so we went to collect it. I have a cycle carrier for the rear of my car. We Loaded it up, and as usual, I went for the "I dont want this falling off" kind of Extra secure approach... sometimes my Family does teh "Here we go again" eye roll when I do this?.... The tie down straps on the carrier, I gave an extra tug "Just to make sure" and one of them snapped..... Just HOW a Nylon strap designed to work in all weathers could degrade that much I have no idea. This is Me though, and I had some spare ratchet straps in the boot.... why do I carry them at all times?.. because just like then, you never know when you will need one...... There is a phrase in Transport sometimes over used, "Due Diligence". What that means is we check as much as reasonably possible for errors.... But what is Reasonably?... Additional Testing suggested.... Roller-skate (oops... ) CAR... laden by the "Just throw it in" method, vs, Loaded up properly with heavy objects down low. Car with reasonable load vs car OVERladen (Say 5 up with heavy luggage weight in a 5 seat family car) Car with Roof-rack secured load. (You can play with secure and insecure here if you wish?....) Light Truck, of the kind you can drive on a car licence....in UK, thats a Transit Van, 2.3 ton, not sure what USA version of that is?... Compare one loaded by the "just chuck it in until its full" average person method against the experienced professional van driver. Again play with Secure/Insecure, and weight issues.... I suspect a question here on why the comparison of loading methods... I have a theory that may be a myth, but I suggest its a reasonable theory, that there is a right and a wrong way to load up, and if Heavy objects are placed over the top of Light objects (the just throw it in method) this raises the centre of gravity as compared with a properly loaded vehicle, thus throwing the weight forward under braking... If I am right, this puts more braking on the front wheels.... If the vehicle is loaded properly, you get equal braking on all four wheels.... I suggest equal braking on all four will give better stopping distance than an equal weight badly loaded vehicle, so I suggest a comparison to test that. I know some may argue either way on the above point, but even if the answer is obvious to us here, the "Enlightened Few" regulars of this board, I suggest that my observation of the general public in action loading up Vans to move stuff, the "Just throw it in" method is considered acceptable by more people than is safe?..... Obviously, the main point is can a fully loaded dedicated transport vehicle stop as fast as a car... I suggest solo (Bob-Tail) cab against a car 0-40 and 40-0, just to show the difference..... Then do the same with a trailer. Both Car AND Wagon. I suggest a non-trailer pulling car driver member of the crew be allowed to stomp brakes and have a car trailer jackknife them.... I also suggest at some point a trailer jackknife of a 60ft trailer be done that is set up to demolish a couple of cars as it swings.....and strap a disposable camera on top of those cars..... Additional from another thread... Can it be tested on how fast you can stop a bus with Passengers on board without causing Injury..........
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Post by the light works on Dec 30, 2012 14:57:38 GMT
the loading comparisons are all a good idea, but I think at that point we diverge into two different topics.
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Post by WebDragon on Dec 31, 2012 1:15:36 GMT
the loading comparisons are all a good idea, but I think at that point we diverge into two different topics. It does diverge from SDs OP. After my DoE proposal, I added the ramp it up stuff including "unsecured loads", because vehicles stopping under controlled situations may be an eye opener for some, but it's hardly "good TV". We can certainly include some "ramp it up" ideas (and I think we should), but we really ought to define the initial experiment first. The "ramp it ups" purposely defy the ASSUMPTIONS. ie: faulty pressure relief valve on a water heater. They permit failure modes for which corrective actions or redundant systems ARE in place, yet have been defeated. That said, I purposely omitted METHODOLOGY and DATA COLLECTION from the DoE until we further settle on precisely WHAT we would like to propose to the producers. We have a good "round table" discussion going, but it needs to be "white boarded" into a coalesced proposal. Feel free to copy/paste my above framework along with your own edits/contributions to build on this idea. (using colour for distinction will help). As per usual, ANALYSIS and CONCLUSION will be left to the "crew".
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Post by silverdragon on Jan 2, 2013 10:44:36 GMT
Loading does affect braking distances.....
This I **Know**.....
However, how can I actually prove this?... Its something I know from experience of doing the job, I know a badly loaded 5 tons wont stop as fast as a properly loaded vehicle, but is that me just "adjusting" my braking to compensate or is it based on load dynamics, or is it a combination of all of that?... I just dont know.
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Post by the light works on Jan 2, 2013 15:41:28 GMT
Loading does affect braking distances..... This I **Know**..... However, how can I actually prove this?... Its something I know from experience of doing the job, I know a badly loaded 5 tons wont stop as fast as a properly loaded vehicle, but is that me just "adjusting" my braking to compensate or is it based on load dynamics, or is it a combination of all of that?... I just dont know. back in my days of working for someone else, I once had someone else load a bundle of conduit on my van for me. It did affect my overall stopping distance. which is to say the van stopped as it always did; and I reminded myself to NEVER trust someone else to load my material.
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Post by silverdragon on Jan 3, 2013 9:05:57 GMT
Now there is a question...... The load its self?.. does that affect the driving?... Evolution of the Myth with a separate set of parameters...maybe?...
I highly suspect it may be true of myself, but is awareness of the actual load responsible for how we handle it, and does that affect the way we brake?.........
Suggestion... a seasoned driver is given two sealed crates (Of similar size and weight) to deliver as separate loads. On the same Wagon, but as different runs. The first crate the driver is informed as waste products for recycling. The Second crate is labelled "Fragile Glass", and the driver is warned its to be handled with care.
Fit sensors to the brake pedal to record how much braking is applied.....
Allow a "Reasonable" run, say 10 miles, through REAL traffic..., on a route that the driver is already familiar with.... preferably with a Wagon the driver is already familiar with as well. (Having to do a "New" run to a strange destination may affect how the driver drives?... I always drive extra careful if I am going somewhere I dont know or have not visited for a while...)
At the designated delivery point, set up an brake-test Emergency Stop situation on the car-park.... the driver will be aware that this will happen...
Then compare the results from the brake sensors?....
I am suspecting the two loads WILL have very different braking characteristics?.... I am also suspecting the Fragile run may take slightly longer to do.... as the driver will be driving with greater care....
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Post by the light works on Jan 3, 2013 14:59:41 GMT
add accelerometers as well. that will tell you more than brake pressure alone.
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Post by srmarti on Jan 4, 2013 3:12:33 GMT
How are you going to assure the driver safety testing what an unsecured load does? Going to make it a remote control truck or tow it at a test facility? Not too interested in seeing them duplicate crash tests. The real thing is no doubt available on line and real crashes are on the new frequently enough. I'm not a fan of gratuitous explosions, granted many fans are. what part of" - vehicles are fit to travel per US transportation regulations. - vehicles are laded per US transportation regulations. implies an unsecured load, to you? This part: The above is just the beginnings of a development plan, please "quote it" and contribute as needed. As we all know, the MBs like to ramp it up!, unsecured loads, stray obstacles, C4 or Cruise missles can all play into making this episode more palatable to their demographic. Feel free to add the ridiculous beyond the reasonable, which demonstrates scale.
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Post by the light works on Jan 4, 2013 3:16:25 GMT
what part of" - vehicles are fit to travel per US transportation regulations. - vehicles are laded per US transportation regulations. implies an unsecured load, to you? This part: The above is just the beginnings of a development plan, please "quote it" and contribute as needed. As we all know, the MBs like to ramp it up!, unsecured loads, stray obstacles, C4 or Cruise missles can all play into making this episode more palatable to their demographic. Feel free to add the ridiculous beyond the reasonable, which demonstrates scale. yes. someone else had mentioned that after I posted.
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Post by silverdragon on Jan 4, 2013 10:31:02 GMT
Taking my last idea.... Can you chuck in a Novice driver, "Just for fun", one who has good reasonable road skills, as in has a relevant licence, but not much experience with "fragile" or otherwise sensitive loads, and see if he does drive differently?.... or is it just the seasoned driver that brakes a sensitive load "Intuitively" more gently?....
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Post by the light works on Jan 4, 2013 14:10:43 GMT
Taking my last idea.... Can you chuck in a Novice driver, "Just for fun", one who has good reasonable road skills, as in has a relevant licence, but not much experience with "fragile" or otherwise sensitive loads, and see if he does drive differently?.... or is it just the seasoned driver that brakes a sensitive load "Intuitively" more gently?.... I think you might find the opposite is true - I think the novice driver will brake more timidly, but have higher accelerometer readings, (due to getting the braking rates wrong) while the seasoned driver will brake more firmly, but have smoother accelerometer readings.
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Post by silverdragon on Jan 4, 2013 16:20:53 GMT
I was expecting, rather from "SWIFT" drivers as you called 'em, that the novice would be harder on the vehicle, and think its some form of race?... Younger drivers are harder on the vehicles... that I know from experience.... Your average seasoned driver such as Us may be "Get there when we get there".... Obviously a little hurry if we have a flashing roof-rack emergency vehicle such as YOUR work TLW.... but even so, I suspect seasoned emergency workers dont take Un-neccesary risks for those extra 10 seconds would they?...
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Post by the light works on Jan 5, 2013 1:19:19 GMT
I was expecting, rather from "SWIFT" drivers as you called 'em, that the novice would be harder on the vehicle, and think its some form of race?... Younger drivers are harder on the vehicles... that I know from experience.... Your average seasoned driver such as Us may be "Get there when we get there".... Obviously a little hurry if we have a flashing roof-rack emergency vehicle such as YOUR work TLW.... but even so, I suspect seasoned emergency workers dont take Un-neccesary risks for those extra 10 seconds would they?... my premise is that should you need to stop with a load of china on your truck, you will apply .X Gs of braking acceleration from the time you decide to stop to the time you come to a stop, with a ramp up at the beginning and a ramp down at the end; while a novice driver will start out with much lower braking force and then have to increase force to compensate for stopping too slow. and the keyword there is "unnecessary" we teach our drivers that if you don't make it there intact, you have just made the problem bigger. but on the other time, if the house is burning and I need to be there to rescue someone inside, those brakes will be HOT when I hit the scene. (but not dangerously hot)
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Post by silverdragon on Jan 6, 2013 10:38:39 GMT
On the other hand, I am expecting a Novice driver to under-estimate the time it takes to stop the bigger heavier vehicle, and have to apply more braking later in the attempt to stop... (Having been used to a smaller lighter easier to stop vehicle...)
So who is right?...
This is why I suggest the test?....
For Instance, when I first took my Bus licence, one of my "problems" that I had to work on before I took the test was persistent "late" braking, as my instructor then said... as in, on a Bus, you HAVE to think about Standing passengers who may want "This stop" to get off, and having the passenger sat on the front window is not good.....
It apparently is a common problem with non Bus drivers, we are all used to seated passengers?...
The dealing with that taught me to anticipate stops, and has probably been VERY useful in the way I deal with Fragile loads, and Fluid loads. I now always brake as if I have a 90 yr old Grandma stood at the doors waiting to get off when I stop?... Experience teaches you things.... novice drivers need to get that experience.
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Post by the light works on Jan 6, 2013 15:58:44 GMT
On the other hand, I am expecting a Novice driver to under-estimate the time it takes to stop the bigger heavier vehicle, and have to apply more braking later in the attempt to stop... (Having been used to a smaller lighter easier to stop vehicle...) So who is right?... This is why I suggest the test?.... For Instance, when I first took my Bus licence, one of my "problems" that I had to work on before I took the test was persistent "late" braking, as my instructor then said... as in, on a Bus, you HAVE to think about Standing passengers who may want "This stop" to get off, and having the passenger sat on the front window is not good..... It apparently is a common problem with non Bus drivers, we are all used to seated passengers?... The dealing with that taught me to anticipate stops, and has probably been VERY useful in the way I deal with Fragile loads, and Fluid loads. I now always brake as if I have a 90 yr old Grandma stood at the doors waiting to get off when I stop?... Experience teaches you things.... novice drivers need to get that experience. that's exactly what I was saying.
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Post by c64 on Jan 6, 2013 21:00:17 GMT
The first crate the driver is informed as waste products for recycling. The Second crate is labelled "Fragile Glass", and the driver is warned its to be handled with care. Bad example. In the second case, it's just an insurance problem, in the first case, you can loose your license to drive waste products if something wents bad. Also who would put common cargo into a truck certified to be used with waste products?
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