I did like how, at the end, she said, "You left your gas tank up on the road, so at least we knew you weren't going to catch fire."
Yes, honey, he left one of his fuel tanks up on the freeway, but the other one he took with him.
Oh well. My wife still calls it gas, so...
Semi hauling Yoplait crashes off I-196
Discussion in 'Trucking Accidents' started by camerabrat, Jul 28, 2011.
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Engine brakes (alone) will not cause a jack knife. Engine brakes along with excessive (for the given conditions) braking will cause the drives to break traction and begin a skid. Once this condition exists, the trailer can, through slope of roadway or unbalanced weight of the cargo, or the straight line between tractor and trailer is interrupted, will cause jack knife. Braking alone will cause a jack knife, the engine brakes don't need to be involved.
Tandems that have locked up, or have maladjusted brakes causing one side to apply greater brake pressure than the opposite side, will cause the tandem group to find the path of least resistance....or swing out from straight line perspective to the tractor.
This is why drivers need to learn to apply light pressure to the rig....and in a panic stop, to keep the rig straight and clean. Swerving to avoid is the most common scenario of jack knife events! Breaking the straight perspective, along with excessive braking, brings the trailer around....be it dry, wet, or icy....braking needs to be done properly.doubledragon5 Thanks this. -
as per he manufacturer:
Slippery PavementSince the operation of any vehicle under slippery conditions is
unpredictable, be sure you have plenty of distance when testing service
brakes or your Jacobs Engine Brake™.
The Jacobs Engine Brake will not affect the operation of ABS (Anti-lock
Braking System) on vehicles so equipped. The ABS systems should
deactivate the engine brake when wheel slip occurs and traction is lost,
and will reactivate the engine brake when the ABS system has
disengaged.
If the Jacobs Engine Brake is new to you, it is recommended that you do
not attempt to use it on slippery roads until you have some experience
with it on dry pavement. When you have that experience, you may use the
following operation sequence as a guideline.
Do not use the Jacobs Engine Brake when bobtailing
or pulling an empty trailer on wet or slippery
pavement, especially when operating a single drive
axle vehicle.Slippery Pavement Driving ProceduresWhen driving on wet or icy pavement, start with the master switch in the"Off" position and use the same gear you would normally use under these
conditions.
Before activating the engine brake, be sure that you have plenty of
distance between your vehicle and other vehicles and that traffic
conditions allow for testing of vehicle braking. Also make sure that the
vehicle is maintaining traction and stability using the natural retarding of
the engine alone. If the retarding of the engine alone without the engine
brake causes any loss of traction, do not attempt to use the engine brake
until road conditions improve.
Jacobs Engine Brake™ Operator's Manual 11
from what I understand from the material is: in slippery conditions, test your jake, if you break traction/lose road grip, SHUT OFF JAKES. Road conditions change. You might be able to engage jakes at first, then as you travel, road conditions worsen, then you lose grip/ break traction. Reaction time is a factor from the time you sense contact loss to the time you flip the off button and hope you caught it in time. It is probably best to just leave them off in slippery conditions, for safety's sake. But to each their own.
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Read it closely....they really don't take a rigid stance on the use or non-use of the Jakes! They do acknowledge that their product is usable in wet/slippery conditions, and offer some "advice" on their recommendations for its use. -
Now we're talking about two different conditions here... one with the tires rolling, and one with the tires sliding - once a tire starts sliding, the coefficient of friction changes drastically, and that alters the force on that tire from the surface its on.
If anything causes the drive tires to break loose from the surface and start sliding, you have a condition where the trailer shoving forward onto the tractor can cause the combination to start to pivot around the fifth wheel... since the center of gravity isn't located there, it will cause a torque around the physical connection between the two parts of the vehicle. Same with a strong wind... any good side force should be capable of causing that torque. The pressure on the ground from the tires counteracts any side force normally, keeping things moving down the road.
As long as you don't have the tractor pushing back on the fifth wheel the stack goes forward even with a tire sliding for whatever reason... but you'll probably feel it in the seat of your pants though. If the the tractor is pushing backwards from the jake brake, then the difference in the normal force on the side with the tire sliding vs the side with the tire rotating can cause enough torque around the center of gravity of the vehicle to get the fifth wheel out of alignment with the velocity vector at the center of gravity. At that point the decelleration force from the jake brake is pushing against the fifth wheel/kingpin pivot point, and the trailer center of gravity (not located there) will cause a torque around the fifth wheel/kingpin pivot - and that will cause a jack knife condition.
...anyway, that's how I see the forces acting.
Ah... if y'all want to risk your Otter testing this theory, have at it! Personally, I think I'll stick with judicious non-use of jakes on slippery surfaces, and go with the side of me that figures pushing your luck on ice, snow-pack or a lot of water on a road with a 80,000 lb vehicle and other folks lives on the line will eventually lead you to a velocity vector counter to a proposition that includes continued employment in the truckin' industry!Last edited: Aug 4, 2011
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Now...you and I would have to order a pot of coffee for discussions over the table....a cup would not suffice! But we would have to agree to pause every once in a while for a chance to hear what the other was actually saying!!!!! LOL -
In this situation... I don't think the jakes alone started the accident in the OP. My guess is something else caused him to apply a lot of braking force - maybe another vehicle doing something stupid (Nah?? You think those chowder-heads in 4-wheelers would do somethin' stupid in front of a semi???) - or he was going too fast for conditions in those curves - probably the case considering the end result. A lot of braking, jakes on to contribute to the mess, enough water to start some hydroplaning, one of those unfortunate velocity vector combinations... and the guy chose the "bushes" as a way out to avoid mushing some 4-wheelers into goo.
Any of us could get caught up in a situation like that... but since there's a big "PRIME" on the side of the trailer, its obvious that the driver was a sub-normal mental midget being goaded on by an evil trucking company. At least that's what the supertruckers would have us think. Its illustrative that when something goes wrong driving one of these things that quite often we have the choice of an accident, or going off the road to avoid the accident. So you have to ask yourself, when things get stacked up against you, what are you going to do???
A while back there was a semi driver who avoided an accident on one of the toll bridges in Baltimore... 18-or-so-year-old kid driving drunk from a privileged, wealthy family cuts off the semi. The driver goes off of the bridge to avoid the accident. Now if it had said "PRIME" on the side of the trailer, you'd have everyone assuming that the driver was an idiot, second guessing his actions, and making ridiculous claims about his abilities. In this case, the driver was a 20-something year industry veteran, and I believe in his own rig. They delayed testing the kid for alcohol for HOURS (probably the attorneys had a hand in that) to get her blood-alcohol content down because of the family connections - in order to blame the truck driver for the accident. The industry was calling him a "hero" for not mushing the kid into goo. Go figure.Last edited: Aug 4, 2011
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Just 1 off the wall question.........
Is it really better to swerve to miss a vehicle, which causes loss of control.
Or NOT swerve, and retain most or some control.................. -
...ummm don't the safety guys call that "counter steering?"
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