How long does it take a truck to stop & is it criminal if he doesn't?

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richard wrote:

Even worse when it looks like the grade drifts to the inside of the curve. The tractor moving right just cracked the whip on the trailers.

Yep, descending grades are just one place you don't try to keep up with the flow of traffic.

BTDT pulling doubles with a flat nose K-worth.
--
Steve W.

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On Fri, 11 Jul 2014 16:48:22 -0400, Retired wrote:

I believe that formula is for a car. Probably developed by some engineer who never had a driver's licemse or drove a car.
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and my own personal experience. DUH!
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On 7/11/2014 7:56 PM, Pico Rico wrote:

[snip]

My error. My comment applies to a "slide to stop" situation where the wheels lock up. When a vehicle slides to a stop under the conditions cited above, the weight is irrelevant.
Source? Google J. Stannard Baker, Professional Engineer, founder of what was known as The Traffic Institute at Northwestern University. He's basically the "father" of crash investigation.
As I recall, the downward force created by the weight of the vehicle balances out the lighter weight of the second vehicle by increasing the effectiveness (for want of a better word) of the coefficient of friction. That's why you don't see the weight listed in that particular formula.
Lotsa strange stuff happens when wheels lock up. Loss of control, cars wind up bass ackwards.
Find yourself a vacant level, parking lot with a bit of rain to liven things up. Drive in a straight line at 25 -30 m/h and without touching the brake pedal, pull up hard on the parking brake (locking the rear wheels) and tell us what you see. Hint: You'll find yourself looking at where you've been rather than where you are headed<g>
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On Friday, July 11, 2014 9:42:42 PM UTC-4, Unquestionably Confused wrote:

I see your point and agree that it makes sense that the more weight, the greater the stopping friction should be. I still question whether it will exactly cancel the effect of the increased momentum. For example, I would wonder if when a tire is locked, skidding, getting super hot, there isn't some limit beyond which additional downward force doesn't do much good. I googled a bit to see if there was some actual real world testing done, but I didn't find anything. I'm sure there must be some testing out there that was done. Would be interesting to see.

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On 07/12/2014 7:38 AM, trader_4 wrote: ...

...
The above approximate model presumes normal static friction force which is proportional to normal force (weight). Since momentum/energy are proportional to m also, they cancel under that assumption.
The problem is,
"In theory there is no difference between theory and practice. In practice there is." -- Jan L. A. van de Snepscheut
It's an extremely limited theory for a very complex problem.
As for research there's actually quite a lot -- one of the more interesting pieces I saw is at
<http://www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0290-o.pdf
--



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On Fri, 11 Jul 2014 19:30:48 -0500, Unquestionably Confused wrote:

You know nothing about real life. "Top Gear" did a demo of this. With just the driver, the car stopped as predicted. Add 3 passengers who all weighed over 300 pounds, it took another 100 feet to stop.
Having been a professional truck driver, it takes much longer to stop a loaded tuck. At 70mph and fully loaded, even longer.
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On 7/11/2014 3:31 PM, richard wrote:

My brother-in-law took one of those courses for a trucker's license. He dropped out when he realized the class was a scam and that the graduates were unfit to drive those big rigs. He said that the situation was quite scary and that it's not safe on the highways with these drivers out there.
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On 7/13/2014 8:20 PM, dsi1 wrote:

That doesn't inspire confidence....
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Christopher A. Young
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On 7/13/2014 2:52 PM, Stormin Mormon wrote:

Luckily, we don't have those giant trucks in this state.
My brother-in-law is a nut for safety. He once was on a job site where they were pouring concrete for a building. He told the foreman that they were not waiting long enough between pours before going to the next level up and that it was unsafe. As I recall, the wet weather messed up the cure times. He quit because he was ignored. A short time later the whole thing collapsed, killing a lot of people. Sometimes they show the video of this on TV. That guy was always kind of a troublemaker but sometimes that's not a bad thing.
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On Fri, 11 Jul 2014 16:32:23 -0400, Steve W. wrote:

I was told 2 to 3 times that.
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richard wrote:

That was the number we used as a baseline for training in ideal conditions in a modern rig. The thing is how many times do you try to leave yourself open braking room only to have 10- 4 wheelers drop into the hole? I know I could never open a hole in most places with traffic, So you do the next best thing, look for ways to slow down and try to leave yourself a way out.
--
Steve W.

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On 7/13/2014 8:20 PM, Steve W. wrote:

I have the same problem, and I drive four wheels. I set up a following distance, and people merge in front of me, one length ahead.
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wrote:

Oh that's funny.
You asked what the skirting on the side of trucks was for.
I answered after a 10 second google search.
You claimed it was illegal to carry a firearm in a commercial vehicle. I proved otherwise.
Maybe you drove trucks, but it's obvious you were fired for incompetence.
--
To reply via e-mail, remove The Obvious and .invalid from my e-mail address.

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On Fri, 11 Jul 2014 12:33:01 -0700, Ann Marie Brest

I can't say how long it takes to stop without knowing the weight of the truck, what kind of brakes, what pavement condition, etc. However, if the driver, by operating an overloaded vehicle at too high a speed with inadequate brakes, and following too closely to allow a safe stopping distance can be considered to be driving carelessly - which can easily be argued, it IS a criminal offence. If someone died from his carelessnes it is arguably vehicular manslaughter - or at the very least careless driving causing death. I believe both of these (at least in Canada - don't know about California) are criminal code violations. I would not want to be in the driver's shoes trying to fight the charge in court.
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On 7/11/14 10:34 PM, snipped-for-privacy@snyder.on.ca wrote:

The weight of the truck doesn't matter for the stopping distance.

No. In California, there's negligent operation, which is a violation of the vehicle code and reckless driving, which is in the penal code.

No. In California, if you're committing an unlawful but non-felony act while driving and you kill someone, then you may be charged with vehicular manslaughter if you acted negligently. Ordinary negligence will get you charged with a misdemeanor; gross negligence may get you charged with a felony.
(If your unlawful act was a felony, you could be charged with felony murder.)

It's impossible to say whether your claim is true that a criminal offense is "easily argued." The driver must have been negligent, i.e., he must have acted recklessly and either knew or should have known he was doing so.
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richard wrote:

You're no fun. Just let it roll; you'll be going slow enough on the grade south of Camp Verde.
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On Fri, 11 Jul 2014 19:30:48 -0500, Unquestionably Confused

Tell that to a proffessional truck driver. The difference in load, brake swept area (number of brakes/tires) will both affect stopping distance significantly. It takes just as much horsepower to accellerate a load from a stop to 60MPH up a hill in a given time or distance as it does to slow the truck from 60MPH to a stop down the same hill. If you double the weight, it will take a lot more time/distance or a lot more horsepower to accellerate the load up the hill - and the same amount more horsepower to stop the truck. That horsepower is absorbed by the brakes when slowing the load, turning it all to heat. The more brakes, the more friction area, and the better the heat dissipation, all else being the same. The hotter the brakes get, the less braking force they can exert due to thermal brake fade (a complete discussion topic on its own) Now the size and number of tires on those braked axles also makes a difference, because if the brakes run out of friction before the tires, the brakes limit the stopping distance. If the tires run out of traction before the brakes, the tires slide. The coefficient of friction of a hot tire sliding on asphalt is significantly different than the coefficient of friction between a warm rolling tire of the same size and the same asphalt. That is a large part of the reason for antilock brakes. Tires braked at the limit of adhesion stop a LOT faster (and with more control) than a sliding locked tire. This is true of almost any road surface.
Now, If the truck has more than adequate brakes, and more than adequate tire for the job, the difference in weight won't matter much. If on the other hand the truck has adequate tires and brakes to handle stopping 40 tons from 60MPH to a dead stop in 600 feet on a 6% grade, he is NOT going to stop 60 tons in the same distance on the same grade, just as it will not stop 40 tons in the same distance on a 12% grade.
The question if it is criminal if he cannot get stopped hinges on several factors. Was the truck loaded within it's GVW rating? If it was overloaded, the driver is on thin ice. Was the driver driving within the posted speed limit? If not, again, he is on thin ice. Was the truck in sound mechanical condition? If not both the driver and owner are now in trouble. Were the air brakes in adjustment, and was the brake check logged in the log book? If not, again the driver is on thin ice.
If the question of whether a prudent driver would have approached that hill at the speed he approached it -even if it was within the speed limit is no, the driver is on thin ice.
It appears limitted driving experience was a major factor in the accident. Unfamiliarity with the road may also have contributed - but if any of the above questions get a "no" answer - - - - .
"Sometimes when you are on thin ice you end up in hot water". .
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You are right!!! in both cases, they ended up with a deadrat!!
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On 7/11/14 11:14 PM, snipped-for-privacy@snyder.on.ca wrote:

I know you're trying to tag the joke with my nym, but I don't think it works. How does a rat fit in with the truck and the car? And if it's me, how did I end up as a contemporary of Galileo?
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