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

You're no fun. Just let it roll; you'll be going slow enough on the grade south of Camp Verde.

Reply to
rbowman
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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". .

Reply to
clare

Sorta. The scene is a crime scene until the investigation is completed.

Harry K

Reply to
Harry K

You are right!!! in both cases, they ended up with a deadrat!!

Reply to
clare

Factors effecting stopping distance:

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As far as stopping distance requirements:

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It may have changed, but when I took the CDL test, the official view was an empty truck would take longer to stop.

Reply to
rbowman

He was going downhill so you have the sign wrong, it should be f-G for this case. That's not a big difference and not your major error. Your major error is thinking that truck tires and truck brakes will come close to the maximum available surface friction of the pavement. For estimating purposes a more realistic effective coefficient of friction would be 0.50. Crunching those numbers gives you around 230 feet.

Reply to
Ashton Crusher

In the real world it would not be immaterial. The empty truck with it's 120psi tires and stiff springs would most likely "bounce" around if the wheels locked which would greatly increase the stopping distance. OTOH, a fully loaded truck might not even be able to come close to locking all the tires or even doing a good job of "braking" them so it too could have long stopping distances. But it extremely unlikely the stopping distances would be the same, in the real world.

Reply to
Ashton Crusher

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.

Reply to
deadrat

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?

Reply to
deadrat

An empty truck will take longer to stop than a properly loded truck - which will stop faster than an overloaded truck.

The load rating of a truck takes into account the tire load rating, the axle load rating,the spring load rating, the braking capacity, and the horsepower and gearing of the prime mover. If there is no Or not enough) weight on the braking wheels, the truck will slide. If there is enough weight on the braking wheels, the tires will hold. If the tires hold more than the brakes, the brakes will limit the stopping distance. If the brakes hold more than the tires, the tires limit the stopping distance. If the brakes and tires are adequate to stop the load, you stop in time. If they are not adequate to stop the load, you do not stop in time. Required Brake horsepower on a grade is determined by the distance travelled in feet times the weight being stopped (ft lbs) devided by the time required to stop it devided by 33000.

1 HP is 33000 ft lbs per minute. So to stop the descent of a 40,000lb truck on a 100 foot high hill hill at 60 MPH in 1320 feet (1/4 mile) over stopping the truck on the level, requires the addition of approxemately 757 HP of braking force. The same amount of extra power it would require to acclerate the same load from 0 to 60 up a 100 ft hill over a quarter mile, over just accellerating it on the level. Double the weight, double the required horsepower. Double the speed, double the horsepower. Double the incline, double the horsepower. Just accellerating, (or stopping) that 40,000 lb truck on the level requiers 475 HP 0-60 or 60-0 in a quarter mile in 25 secconds. Increasing the load to 60000 lbs raises the power required to 715HP Increasing the load to 80000lb requires 950 HP.

SO Lets stop a 40000 lb truck from 60MPH to a dead stop on a 100 ft high

1/4 mile long hill. The brakes will have to dissipate 1232 HP. Double the weight of the truck and the brakes are required to dissipate 2464 HP.Double the incline and the 80000 lb truck requires 3221 HP

Now, not only do we need enough brake to absorb that much Horsepower, we need enough tire to put that 2464 HP to the ground without breaking traction with the road surface. The number of tires on braking axles most definitely comes into play here. (as does the number and capacity of wheel brakes available) - because as stated before, stopping distance is limitted by the lesser of brake power and tire traction.

In the case referenced by the OP, the tires ran out before the brakes as the trailers slid and jacknifed - and if the tired HAD been able to hold all of the braking force, the brakes most likely would still not have been adequate to stop the loaded truck in the time/space allowed from the speed he was going.

Reducing the speed coming into the situation reduces the required braking power for both the decelleration of the load and the control of descent of the load much more than the weight by both reducing the feet per second AND increasing the time/distance available to stop.

Increase the load by 10%, reduce speed by 5% - more or less for the same stopping distance.

I likely missed a few factors that will skew the numbers slightly - but theyw are close and show the "trend"

Weight and tires/brakes as well as speed all have a BIG effect on stopping distance.

Reply to
clare

Ashton Crusher wrote, on Fri, 11 Jul 2014 22:43:24 -0700:

The first article in the OP says that the driver, Ravinderbal Singh, said he jammed on the brakes, which began to smoke, but did little to slow him down.

He's quoted as saying "It wasn't decreasing speed. It kept going up 'cause it was, like, too steep for me,".

Does that indicate the tires or the brakes were the limiting factor in his inability to stop until he had crushed the 10 cars in front of him?

Reply to
Jesse Davis

I question that. I would expect the one with concrete to have far more inertia to overcome than the one that is empty.

Reply to
K Wills (Shill #3)

I thought he was Italian. Wouldn't it been Italian cars? VW is German.

Reply to
Stormin Mormon

The truck would have stopped faster. It has air brakes.

SH

Reply to
Sherlock.Homes

Brilliant deduction!

Reply to
Stormin Mormon

I believe I had asked if the skirting was required by law. As I had not seen skirting like this on trucks while I was an active driver.

I may have. But then also said something else to clarify and you never mention that.

If you have a CCW in state A, you can carry that firearm all you want. Cross the line into state B, who does not issue CCW, and you could go to jail. You can carry a firearm in a ttuck as long as it is properly locked and stored and not within arm's reach. But if you work for a company and the company owns the truck, when they find that firearm, they can and will fire you if they do not allow firearms.

You're the one who is a frickin laughing joke. Claiming to be an expert on any topic.

Reply to
richard

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.

Reply to
trader_4

Actually that was Jeremy Clarkson on "Top Gear". Two different things. When on the moon, Neil Armstrong dropped a bowling ball and a feather at the same time. Both landed at the same time. That works in a vacuum.

And the real experiment was done using a ramp. With various sizes and weights of balls.

Reply to
richard

Not at all. Deceleration is calculated as acceleration, inverted (both are limited by friction limit of tires on pavement).

it's force over mass. If mass didn't count, we'd just move the Space Station up in one go rather than a hundred trips!

And that's why my 140hp 1 ton car zips around 3500lb cars of similar power.

Reply to
AMuzi

Pico Rico:

Where I'm from a puddle jumper = an amphibious 6-12 passenger prop plane.

In what context are you using the term?

Reply to
thekmanrocks

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