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Tesla Autopilot, fatal crash into side of truck 6
- Thread starter VEBill
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Maybe they won't see deer on the road, or they might over react.
My normal commute includes a two lane road with passing lanes every few miles, then it turns into a divided 4 lane with several ill timed stop lights, and a speed change or two.
Seem to find tailgaters on the two lane part. And although parts allow passing, there is usually too much traffic.
At times several road kill deer can be seen along the road, though I rarely see a car or truck nearby (perhaps people keep driving).
Amazing that people seem to miss the signs that say "Keep right except to pass". So I would ask if the self driving cars or trucks can understand the signs any better? Or is it like the GPS that never gets updated.
What subroutine allows it to avoid road damage, or blown tire parts?
My normal commute includes a two lane road with passing lanes every few miles, then it turns into a divided 4 lane with several ill timed stop lights, and a speed change or two.
Seem to find tailgaters on the two lane part. And although parts allow passing, there is usually too much traffic.
At times several road kill deer can be seen along the road, though I rarely see a car or truck nearby (perhaps people keep driving).
Amazing that people seem to miss the signs that say "Keep right except to pass". So I would ask if the self driving cars or trucks can understand the signs any better? Or is it like the GPS that never gets updated.
What subroutine allows it to avoid road damage, or blown tire parts?
- Thread starter
- #203
Amazing that people seem to miss the signs that say "Keep right except to pass".
>> not surprising at all; the right lanes are slower, so why get stuck in them?
So I would ask if the self driving cars or trucks can understand the signs any better?
>> All that stuff has been digitized; which is why almost all the nav systems show speed limits, one-way, and number of turn lanes, etc.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529
>> not surprising at all; the right lanes are slower, so why get stuck in them?
So I would ask if the self driving cars or trucks can understand the signs any better?
>> All that stuff has been digitized; which is why almost all the nav systems show speed limits, one-way, and number of turn lanes, etc.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529
Ont thing nice about living in a relatively state like California is there's room for adequate signage, which is harder to achieve with a 200-yr old road structure.
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529
LionelHutz
Electrical
Now you bring up getting used to ABS as if that system has been perfected in the last 20 or 25 years of widespread deployment. That is a complete piss-poor analogy to use when saying we just need to get used to it. We should get used to these self driving cars working "most" of the time without knowing exactly when they might just try to kill us.
The ABS system on the vehicles I have owned have performed like complete and utter crap when on certain snow covered roads. I have to drive according to how piss-poorly the system works instead of driving according to the road conditions because the system takes away almost all the braking force. It can easily add 3 or 4 car lengths to the stopping distance in cases where I'm only going speeds in the 25-30mph range. And this includes it disengaging at 15mph when I begin to apply real braking force that actually stops the car.
The ABS system on the vehicles I have owned have performed like complete and utter crap when on certain snow covered roads. I have to drive according to how piss-poorly the system works instead of driving according to the road conditions because the system takes away almost all the braking force. It can easily add 3 or 4 car lengths to the stopping distance in cases where I'm only going speeds in the 25-30mph range. And this includes it disengaging at 15mph when I begin to apply real braking force that actually stops the car.
BrianPetersen
Mechanical
^ I use the (mechanical cable-operated) hand-brake to intentionally lock the rear wheels in situations like that, and there are times when I wish I could do the same to the front. The ABS is powerless to overrule a mechanical cable going straight to the brake pads. Heaven help if your "parking brake" is a pushbutton that doesn't overrule the ABS.
JohnRBaker
Mechanical
I've found that the ABS systems work quite well, at least they have for me. Now it is true that you have to know how to properly utilize them and that's where the problem occurs. Eventually this problem will tend to mitigate itself as new drivers will be learning only on ABS equipped and therefore they will hopefully NOT BE TOLD TO PUMP THE BRAKES!!!
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
NormPeterson
Structural
ABS works well enough most times it's needed. But there are a few situations where it can and does get it "wrong", to where an experienced driver
who's paying attention can do better. A road contour that suddenly angles down and unloads the tires enough is another example. Like in the
washboard road situation, the problem seems to be that ABS systems generally can't tell the difference between a tire that's sliding because
increasing brake torque has overpowered a reasonably constant amount of contact patch grip or if the amount of contact patch grip itself has
suddenly decreased.
Brian - too much rear brake (or a combination of wheel brake + engine compression braking) in a low-grip situation can be a risky proposition
if, for example, you're going downhill at the time.
In my own experience, ABS has been most useful in preventing expensive tires from getting flatspotted under unusual conditions at a
certain motorsports activity.
Norm
who's paying attention can do better. A road contour that suddenly angles down and unloads the tires enough is another example. Like in the
washboard road situation, the problem seems to be that ABS systems generally can't tell the difference between a tire that's sliding because
increasing brake torque has overpowered a reasonably constant amount of contact patch grip or if the amount of contact patch grip itself has
suddenly decreased.
Brian - too much rear brake (or a combination of wheel brake + engine compression braking) in a low-grip situation can be a risky proposition
if, for example, you're going downhill at the time.
In my own experience, ABS has been most useful in preventing expensive tires from getting flatspotted under unusual conditions at a
certain motorsports activity.
Norm
JohnRBaker
Mechanical
They still running demolition-derbies at county fairs? ![[auto]](/data/assets/smilies/auto.gif "[auto] [auto]")
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
BrianPetersen
Mechanical
No question too much rear brake causes stability issues. That's why I'd also like to be able to lock the fronts, overruling the ABS, but I can't.
Usually these situations aren't happening at 120 km/h anyhow; usually it's more like 20 km/h and the feeling of slowly but inexorably approaching and passing the stop sign while the ABS refuses to allow any braking at all even though a locked wheel at that speed isn't much of a stability issue. Also if this is happening while I'm approaching the back of another vehicle, I really don't care about stability at that point. I just want it to STOP. Doesn't matter if it's frontwards or sideways or backwards, I just don't want to slide into the other car!
And Mr Baker, I suspect by your published location in your signature that you wouldn't have a few months of this to deal with every year
Usually these situations aren't happening at 120 km/h anyhow; usually it's more like 20 km/h and the feeling of slowly but inexorably approaching and passing the stop sign while the ABS refuses to allow any braking at all even though a locked wheel at that speed isn't much of a stability issue. Also if this is happening while I'm approaching the back of another vehicle, I really don't care about stability at that point. I just want it to STOP. Doesn't matter if it's frontwards or sideways or backwards, I just don't want to slide into the other car!
And Mr Baker, I suspect by your published location in your signature that you wouldn't have a few months of this to deal with every year
BrianPetersen
Mechanical
I should add that the handbrake overrule of the ABS is also useful to overcome terminal understeer on similarly snow-covered surfaces. Turn steering wheel ... nothing happens ... momentary judicious handbrake application, and now the car turns. Of course, getting the car to point a different way, and actually changing its direction of motion, are two different things, but getting pointed the right way seems to be half the battle. I think what happens is that the wheel creates a bigger wedge of snow when it's a bit sideways than when it's straight, and the rear brake application transfers a bit of weight forward to help with steering up front.
Will self-driving be able to do this??
Will self-driving be able to do this??
- Thread starter
- #215
My car's ABS allows me to lock up the wheels when (for example) slowly creeping down an icy hill covered in snow.
Used normally, it's the usual 30 Hz ABS chatter. But press the brake pedal just a bit firmer, and one may (by choice) lock up the wheels. I presume only under specific conditions, such as slow speeds.
This slow speed ABS override feature can be very useful in certain conditions. Studded winter tires sometimes need a few seconds to scrub through the raft of snow to reach the ice, where they can provide some braking. Then one releases the brakes enough to regain steering, before going off the edge of the road. Repeat for length of hill. Kinda like manual ABS, but the physics of snow on ice with studded tires needs a cycle time of about four or five seconds to penetrate the snow rafting under the tires, not the usual 30 Hz ABS.
Mercedes. They do seem to know what they're doing.
Used normally, it's the usual 30 Hz ABS chatter. But press the brake pedal just a bit firmer, and one may (by choice) lock up the wheels. I presume only under specific conditions, such as slow speeds.
This slow speed ABS override feature can be very useful in certain conditions. Studded winter tires sometimes need a few seconds to scrub through the raft of snow to reach the ice, where they can provide some braking. Then one releases the brakes enough to regain steering, before going off the edge of the road. Repeat for length of hill. Kinda like manual ABS, but the physics of snow on ice with studded tires needs a cycle time of about four or five seconds to penetrate the snow rafting under the tires, not the usual 30 Hz ABS.
Mercedes. They do seem to know what they're doing.
GregLocock
Automotive
Typically even old school ABS does not intervene at all below a particular speed, of the order of 8 mph. That is quite an interesting thought on ice, since if you manage to lock all 4 wheels then the vehicle speed is zero, and so they'll stay locked. I'd guess that more modern systems model the apparent mu and adjust their strategy accordingly.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
Just a question about self driving trucks. Who puts the chains on the tires? Just simple that at times chains are required.
Maybe that will increase the number of jobs for roadside assistance. Which from my viewpoint needs to be improved.
And maybe it will bring back full service filling stations. (clean that lens sir and/or mam).
How do self driving cars handle tire blowouts?
Good point about snow tires, although I don't use studded snow tires myself. The all season tires just don't preform as well as snow tires.
Maybe there needs to be automotive drivers training on things like tires, breaking, how to fix many common problems, like flat tire. Maybe also to not take fast curves with large things in the back of your truck.
Maybe that will increase the number of jobs for roadside assistance. Which from my viewpoint needs to be improved.
And maybe it will bring back full service filling stations. (clean that lens sir and/or mam).
How do self driving cars handle tire blowouts?
Good point about snow tires, although I don't use studded snow tires myself. The all season tires just don't preform as well as snow tires.
Maybe there needs to be automotive drivers training on things like tires, breaking, how to fix many common problems, like flat tire. Maybe also to not take fast curves with large things in the back of your truck.
JohnRBaker
Mechanical
BrianPetersen said:
If you're referring to driving in the rain, then yes, we're only confronted with that situation a few months out of each year.
But that being said, it's amazing how it seems that when that first rainfall of the season hits, that collectively, nearly everyone in Southern California has totally forgotten how to drive, period. The most accidents, many of them albeit minor, seem to occur on those first few days of rain after a long period of rain-free weather. Granted, some of this can be attributed (and always is by the local media) to the fact then many of the roads get a covering of oil that doesn't mean much when the rods are dry but can become a real problem when the first rain starts to fall.
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
BrianPetersen
Mechanical
Rain?
Subtract quite a few degrees C.
Subtract quite a few degrees C.
JohnRBaker
Mechanical
If you meant 'ice' or 'snow', that was NEVER made clear in your post. And BTW, it snows in Southern California every winter, just that it keeps its distance, up in the mountains, so that you can go visit it on the weekends if you want ;-)
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:
The secret of life is not finding someone to live with
It's finding someone you can't live without
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