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The key part for me was: > [Lawyer] argued that Riad’s actions — driving 74 mph on a surface street — did not rise to “gross negligence” and should not be cons

by trgn 4y ago

The key part for me was: > [Lawyer] argued that Riad’s actions — driving 74 mph on a surface street — did not rise to “gross negligence” and should not be considered a felony. At that speed, the driver's momentum was around 67.000 kg*m/s. That is an impact about 10 times bigger as getting thrown out of a plane and hitting the ground at terminal velocity. I'd say it's gross negligence to drive that fast at all on any surface street with sidewalks, traffic lights, intersections, stores, whether the driver is asleep at the wheel or not, autopilot or not, drugged or not.

iancmceachern 4y ago
I agree, if the speed limit was below 74.
leereeves 4y ago
> I'd say it's gross negligence to drive that fast at all on any surface street Agreed, but Riad set that speed when he was driving on a freeway, and Autopilot failed to slow down when the freeway became a surface street. I think Riad was negligent for not maintaining control of the car (Tesla even warns drivers to "pay extra attention to the road" when using Autopilot or FSD), but I wonder if Tesla has any liability for marketing Autopilot and FSD capabilities that don't always work.
- parkingrift 4y ago
  This was autopilot, which is essentially just advanced cruise control. Full self driving is a completely separate product from Tesla.
  - Hamuko 4y ago
    But advanced cruise controls do slow down if the speed changes. https://youtu.be/LEqM2FqUIa8?t=204 https://youtu.be/LEqM2FqUIa8?t=204 Surely the speed limit would change if there's a light-controlled intersection?
    - parkingrift 4y ago
      Mercedes has it, but most don’t. My CRV has the equivalent to autopilot and maybe would have applied emergency breaking just before impact. Not sure honestly. These advanced cruise control features are not self driving at all. Mine won’t even stay in the lane if I take my hand off the wheel.
      - leereeves 4y ago
        Honda doesn't suggest the CRV is self driving. Tesla marketing encourages the idea that the car can drive itself, in fact it literally will with the Smart Summon feature. That's misleading, so it's not surprising if some people are misled.
        parkingrift 4y ago
        Again, this is not what Tesla calls “full self driving.” No one driving a Tesla would ever be confused about this. The car will flip out if you take your hands off the wheel. Every manufacture has some silly name for advanced cruise control. It’s called marketing.
        leereeves 4y ago
        > No one driving a Tesla would ever be confused about this. Plainly false. Consider this guy, who was seen sleeping at the wheel three times, relying on the car to drive itself: https://www.youtube.com/watch?v=pgnzK07cQkY https://www.youtube.com/watch?v=pgnzK07cQkY
  - jacquesm 4y ago
    "Full self driving is a completely separate product from Tesla." The thing that Tesla has named 'full self driving', but which it isn't is a completely separate product from Tesla.
shadowgovt 4y ago
Small nitpick: that's the impact if the car impacts an immobile structure square-on. Cars don't impact like that; static friction of wheels on road gives out way before the full kinetic energy is imparted to the passenger cabin of the victim vehicle, and then the car is thrown and can clear that energy by skidding instead of further deforming. But the point stands that it's bad and not something we should be structuring our society to encourage.
sandworm101 4y ago
>> At that speed, the driver's momentum was around 67.000 kg*m/s. So? Any large truck moving below the speed limit and being perfectly safe can have vastly more energy. And a speeding motorcycle will have vastly less. In a highly-regulated behavior such as driving, negligence is not a function of energy. It is a matter of law rather than physics.
- dane-pgp 4y ago
  To be fair, Conservation of Energy is a law.
  - sandworm101 4y ago
    Ya, but that law isn't well respected. It hasn't been tested let alone affirmed by any court. It is very likely not constitutional. I would not cite it.
etskinner 4y ago
> At that speed, the driver's momentum was around 67.000 kg*m/s. > That is an impact about 10 times bigger as getting thrown out of a plane and hitting the ground at terminal velocity. That doesn't seem right. Momentum is mass times velocity, p=mv. Average male weight is around 89kg, 74mph is about 33m/s. p_driver=33*89=2937 kg*m/s. Terminal velocity of a skydiver is around 120mph, which is about 54m/s. p_skydiver=54*87=4698 kg*m/s. p_skydiver/p_driver=4698/2937=1.6. So the momentum of the driver is smaller than that of falling at terminal velocity by a factor of 1.6.
- estsauver 4y ago
  I think he means the momentum of the driver+car system, not the momentum of the driver alone.
  - etskinner 4y ago
    Then it doesn't make any sense to compare it to falling out of a plane. No matter what mass you're talking about, it cancels out when you compare it to another velocity, so the factor would still be 1.6, not 10.
  - malfist 4y ago
    In that case, to keep equivalent comparisons, shouldn't we compare the momentum of a driver+car system and a pilot+plane system? Clearly GP's physics experiment makes little sense.
butwhywhyoh 4y ago
This momentum argument doesn't follow. First you calculate the momentum of the vehicle, then you compare it to an impact without describing exactly what you're comparing. However, the momentum of the vehicle will absolutely not be completely transferred to the person in an collision, and so will be not much like hitting the ground at terminal velocity. And why are we talking about momentum anyways? A fully loaded tractor trailer weighs about 80,000 lbs (~ 36,000 kg). Therefore, a tractor trailer traveling at 5 mph (~2 m/s) has a total momentum of 72,000 kg*m/s. By your argument, all tractor trailers driving through a city are grossly negligent.
- engineeringwoke 4y ago
  It's just another engineer being an armchair physicist. Nothing to be alarmed about
  - sandworm101 4y ago
    An engineer being an armchair physicist being an armchair lawyer.
  - bozhark 4y ago
    The _numbers_ Mason, they mean something!
- kube-system 4y ago
  And getting shot with a handgun is around 2 or 3 kg*m/s. Much less negligent, clearly!
  - trgn 4y ago
    You die from the perforation wound and organ damage, not the impact.
    - kube-system 4y ago
      I understand, that’s (part of) my point. The transfer of momentum is more important than how much exists. But more broadly, negligence isn’t measured in kg*m/s.
jjav 4y ago
> That is an impact about 10 times bigger as getting thrown out of a plane and hitting the ground at terminal velocity. Even without computing any numbers, purely at the sanity-check level, this calculation is clearly wrong. Think about it. While there have been some recorded incidents of people surviving a free-fall impact to the ground, that's mostly a certain death impact. Even if survived, you are in very bad shape (understatement). An impact 10x worse than that would completely destroy your body. Then compare to race car drivers routinely having crashes at speeds higher than 74mph and most of the time hopping out of the car with no injury. Even at much much higher speeds. The flaw in the argument is summarized in the common saying "It's not the speed that kills you it's the sudden stop". If you hit the ground from an airplane, the stop is very sudden, leading to extreme instantaneous g loads. That's what kills, not the absolute value of the speed itself. In car crashes there is a lot of energy dissipation due to both structural crumple zones as well as motion of the car itself (it might spin, flip, skid more, etc). These factors lenghten the deceleration time and thus greatly reduce the g loads on the body.
- deleted 4y ago
  [deleted]
throwaway0a5e 4y ago
>driving 74 mph on a surface street I really hate these kinds of words. A four lane "basically an interstate if it weren't for the traffic lights every couple miles" type boulevard or state highway typical of urban/suburban areas of sprawl type construction and a two lane residential street are both surface roads. And there's tons of both of those types of roads in the LA area (where this crash took place). There's a big difference between driving 74mph on a somewhat limited access boulevard vs driving 74mph on a residential street.

by trgn 4y ago

iancmceachern 4y ago

I agree, if the speed limit was below 74.

leereeves 4y ago

> I'd say it's gross negligence to drive that fast at all on any surface street Agreed, but Riad set that speed when he was driving on a freeway, and Autopilot failed to slow down when the freeway became a surface street. I think Riad was negligent for not maintaining control of the car (Tesla even warns drivers to "pay extra attention to the road" when using Autopilot or FSD), but I wonder if Tesla has any liability for marketing Autopilot and FSD capabilities that don't always work.

parkingrift 4y ago
This was autopilot, which is essentially just advanced cruise control. Full self driving is a completely separate product from Tesla.
- Hamuko 4y ago
  But advanced cruise controls do slow down if the speed changes. https://youtu.be/LEqM2FqUIa8?t=204 https://youtu.be/LEqM2FqUIa8?t=204 Surely the speed limit would change if there's a light-controlled intersection?
  - parkingrift 4y ago
    Mercedes has it, but most don’t. My CRV has the equivalent to autopilot and maybe would have applied emergency breaking just before impact. Not sure honestly. These advanced cruise control features are not self driving at all. Mine won’t even stay in the lane if I take my hand off the wheel.
    - leereeves 4y ago
      Honda doesn't suggest the CRV is self driving. Tesla marketing encourages the idea that the car can drive itself, in fact it literally will with the Smart Summon feature. That's misleading, so it's not surprising if some people are misled.
      - parkingrift 4y ago
        Again, this is not what Tesla calls “full self driving.” No one driving a Tesla would ever be confused about this. The car will flip out if you take your hands off the wheel. Every manufacture has some silly name for advanced cruise control. It’s called marketing.
        leereeves 4y ago
        > No one driving a Tesla would ever be confused about this. Plainly false. Consider this guy, who was seen sleeping at the wheel three times, relying on the car to drive itself: https://www.youtube.com/watch?v=pgnzK07cQkY https://www.youtube.com/watch?v=pgnzK07cQkY
- jacquesm 4y ago
  "Full self driving is a completely separate product from Tesla." The thing that Tesla has named 'full self driving', but which it isn't is a completely separate product from Tesla.

shadowgovt 4y ago

Small nitpick: that's the impact if the car impacts an immobile structure square-on. Cars don't impact like that; static friction of wheels on road gives out way before the full kinetic energy is imparted to the passenger cabin of the victim vehicle, and then the car is thrown and can clear that energy by skidding instead of further deforming. But the point stands that it's bad and not something we should be structuring our society to encourage.

sandworm101 4y ago

>> At that speed, the driver's momentum was around 67.000 kg*m/s. So? Any large truck moving below the speed limit and being perfectly safe can have vastly more energy. And a speeding motorcycle will have vastly less. In a highly-regulated behavior such as driving, negligence is not a function of energy. It is a matter of law rather than physics.

dane-pgp 4y ago
To be fair, Conservation of Energy is a law.
- sandworm101 4y ago
  Ya, but that law isn't well respected. It hasn't been tested let alone affirmed by any court. It is very likely not constitutional. I would not cite it.

etskinner 4y ago

> At that speed, the driver's momentum was around 67.000 kg*m/s. > That is an impact about 10 times bigger as getting thrown out of a plane and hitting the ground at terminal velocity. That doesn't seem right. Momentum is mass times velocity, p=mv. Average male weight is around 89kg, 74mph is about 33m/s. p_driver=33*89=2937 kg*m/s. Terminal velocity of a skydiver is around 120mph, which is about 54m/s. p_skydiver=54*87=4698 kg*m/s. p_skydiver/p_driver=4698/2937=1.6. So the momentum of the driver is smaller than that of falling at terminal velocity by a factor of 1.6.

estsauver 4y ago
I think he means the momentum of the driver+car system, not the momentum of the driver alone.
- etskinner 4y ago
  Then it doesn't make any sense to compare it to falling out of a plane. No matter what mass you're talking about, it cancels out when you compare it to another velocity, so the factor would still be 1.6, not 10.
- malfist 4y ago
  In that case, to keep equivalent comparisons, shouldn't we compare the momentum of a driver+car system and a pilot+plane system? Clearly GP's physics experiment makes little sense.

butwhywhyoh 4y ago

This momentum argument doesn't follow. First you calculate the momentum of the vehicle, then you compare it to an impact without describing exactly what you're comparing. However, the momentum of the vehicle will absolutely not be completely transferred to the person in an collision, and so will be not much like hitting the ground at terminal velocity. And why are we talking about momentum anyways? A fully loaded tractor trailer weighs about 80,000 lbs (~ 36,000 kg). Therefore, a tractor trailer traveling at 5 mph (~2 m/s) has a total momentum of 72,000 kg*m/s. By your argument, all tractor trailers driving through a city are grossly negligent.

engineeringwoke 4y ago
It's just another engineer being an armchair physicist. Nothing to be alarmed about
- sandworm101 4y ago
  An engineer being an armchair physicist being an armchair lawyer.
- bozhark 4y ago
  The _numbers_ Mason, they mean something!
kube-system 4y ago
And getting shot with a handgun is around 2 or 3 kg*m/s. Much less negligent, clearly!
- trgn 4y ago
  You die from the perforation wound and organ damage, not the impact.
  - kube-system 4y ago
    I understand, that’s (part of) my point. The transfer of momentum is more important than how much exists. But more broadly, negligence isn’t measured in kg*m/s.

jjav 4y ago

> That is an impact about 10 times bigger as getting thrown out of a plane and hitting the ground at terminal velocity. Even without computing any numbers, purely at the sanity-check level, this calculation is clearly wrong. Think about it. While there have been some recorded incidents of people surviving a free-fall impact to the ground, that's mostly a certain death impact. Even if survived, you are in very bad shape (understatement). An impact 10x worse than that would completely destroy your body. Then compare to race car drivers routinely having crashes at speeds higher than 74mph and most of the time hopping out of the car with no injury. Even at much much higher speeds. The flaw in the argument is summarized in the common saying "It's not the speed that kills you it's the sudden stop". If you hit the ground from an airplane, the stop is very sudden, leading to extreme instantaneous g loads. That's what kills, not the absolute value of the speed itself. In car crashes there is a lot of energy dissipation due to both structural crumple zones as well as motion of the car itself (it might spin, flip, skid more, etc). These factors lenghten the deceleration time and thus greatly reduce the g loads on the body.

deleted 4y ago
[deleted]

throwaway0a5e 4y ago

>driving 74 mph on a surface street I really hate these kinds of words. A four lane "basically an interstate if it weren't for the traffic lights every couple miles" type boulevard or state highway typical of urban/suburban areas of sprawl type construction and a two lane residential street are both surface roads. And there's tons of both of those types of roads in the LA area (where this crash took place). There's a big difference between driving 74mph on a somewhat limited access boulevard vs driving 74mph on a residential street.