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If a Model 3 decides to emergency brake without warning, can the driver still steer it to the shoulder of the highway, or are steering commands from the driver

by dhx 5y ago

If a Model 3 decides to emergency brake without warning, can the driver still steer it to the shoulder of the highway, or are steering commands from the driver ignored? I'm guessing the first car crashed into the rear of the Model 3, causing the Model 3 to spin out into another lane. Then a second car crashed into the Model 3 (probably side impact?) as it was now very dangerously exposed to oncoming traffic in the other lane. If the driver could have steered the vehicle during the emergency braking to the shoulder of the highway they'd likely still be alive. Unfortunately if the highway was heavily congested and this driver was sandwiched between vehicles on either side, there is probably nothing additional the driver could have done to improve the situation. From the linked Facebook post there is the following comment: My husband unfortunately was one of the drivers that struck the Tesla. He said the car in front of him almost hit the car so they swerved barely missing him and then there was the Tesla right there . He absolutely could not of stopped in time. It's a very traumatic situation. My husband is now dealing with survivors guilt and is taking it extremely hard. We are so very sorry this happened....I have no doubt that the gentleman that lost his life was loved by many and God help us all to find some strength to deal with the grief.

staktrace 5y ago
To reply to your first question: if the car decides to emergency brake, you can still override it by pressing the accelerator. In my experience, the braking that happens is "hard" but no more hard than you would do yourself if something suddenly appeared in your drive path, and if you are paying attention you can press the accelerator within a second or so. If the person behind you has adequate following distance it shouldn't be a problem. If the car loses power entirely then it gives you a few seconds warning in which you may or may not be able to cross to the shoulder before the car coasts to a stop. In this scenario the braking is not "hard", but obviously there is no real way to recover and you'll need to get towed. I have not experienced any scenario where the car does not respond to steering or acceleration commands when it was physically able to do so.
- staktrace 5y ago
  Self-reply to add: despite (occasionally) experiencing phantom braking and my wife once experiencing the "loss of power" scenario due to a defective drive unit, I'm still very happy with the Tesla overall. In my experience it is the best car I've owned despite the flaws that seem to disproportionately make the headlines.
- mysterydip 5y ago
  if it emergency brakes, does steering still work or not until you accelerate?
  - jeofken 5y ago
    Yes - a slight nudge on the steering wheel or pedals deactivates autopilot. You always have full control like when driving like normal. One should therefore always have the hands on the wheel and feet by the pedals and be ready to drive.
    - rootusrootus 5y ago
      > slight nudge To clarify, this only applies if the car doesn't think you're about to exit the lane. It will momentarily fight you, and it will take more than a slight nudge to override it.
  - staktrace 5y ago
    It does work, yes.
- mellavora 5y ago
  > if something suddenly appeared in your drive path, and if you are paying attention you can press the accelerator within a second or so. So if something appears in your path, the right course of action is to accelerate into it? within a second or so is great but not if you have 1/4 second time to respond. > If the person behind you has adequate following distance it shouldn't be a problem. Nice assumption. > If the car loses power entirely then it gives you a few seconds warning in which you may or may not be able to cross to the shoulder before the car coasts to a stop. may or may not indeed.
  - vladvasiliu 5y ago
    > So if something appears in your path, the right course of action is to accelerate into it? Not into it, but around it – if possible, of course. It's something you learn in motorcycle school, for example. The idea is that a motorcycle is harder to maneuver while under hard braking, so you have a better chance of avoiding the obstacle or falling by going around it. >> If the person behind you has adequate following distance it shouldn't be a problem. > Nice assumption. Of course. This also feeds into the above. As in, not only do you have to stop, but also to make sure that the person following you will stop without hitting you.
  - jazzyjackson 5y ago
    > So if something appears in your path, the right course of action is to accelerate into it? >> ...the braking that happens is "hard" but no more hard than you would do yourself if something suddenly appeared in your drive path... parent post was just giving a comparison to the deceleration-snap experienced during phantom braking, and saying in the event of a phantom brake, you can cancel the event by tapping the gas (battery?) pedal
  - deleted 5y ago
    [deleted]
  - staktrace 5y ago
    > So if something appears in your path, the right course of action is to accelerate into it? You mis-parsed what I said here. My sentence was probably too long. Let me try using shorter ones. Say you are driving. Suddenly a squirrel appears on the road 50m away. You apply brakes "hard" to avoid hitting it. This amount of braking is what the car does. You can still press the accelerator. The accelerator works as expected, cancelling the software's braking. > if you have 1/4 second time to respond. Under what circumstances would you have this short amount of time? IMO only if somebody is following you too closely. Again, remove the software from the equation and insert the aforementioned squirrel. You brake hard for it. The person behind rear-ends you because they were following too closely. Who is at fault? > Nice assumption Thank you
rileymat2 5y ago
> He said the car in front of him almost hit the car so they swerved barely missing him and then there was the Tesla right there. This is not a criticism of the driver, because everyone does it, but one of my pet peeves is hardly anyone follows at a safe distance. Most of the time you can’t even if you want to because someone will merge in front of you with that much space.
- Iolaum 5y ago
  So true!
- dahfizz 5y ago
  > Most of the time you can’t even if you want to because someone will merge in front of you with that much space. This annoys me so much. It creates a game theory situation where everybody has to drive like an asshole in order to avoid being cut off by assholes.
  - mattcwilson 5y ago
    Seems like the game theory being applied there is a bit of prisoners dilemma. Is playing “asshole” the right move?
    - pclmulqdq 5y ago
      In California, unfortunately, the answer seems to be "yes." When I moved to the northeast US, drivers were more sane on highways.
      - tfigment 5y ago
        When I moved to Boston, the first lesson I learned was any gap in front of me that can fit a car will soon have one there. I think it is big cities in general not just regions.
        lotsofpulp 5y ago
iso1631 5y ago
> He absolutely could not of stopped in time. Somebody (not necessarily the husband) was driving too close to the car in front. You should have enough time to see the car stopping and stop yourself. A 2 second gap at 60mph is 178 feet. A second to react and that still gives you 88 feet to slow down in before you even get to the point where the Tesla started to slow, reducing the impact speed to far lower -- not enough that should kill anyone.
- jazzyjackson 5y ago
  crowded expressways have a way of filling gaps
- reallydontask 5y ago
  Not necessarily the case. Friend of mine was on the middle lane on the motorway when somebody switched on to his lane and braked hard. He crashed against but wasn't deemed at fault by insurance. Not saying that this is what happened, btw.
alistairSH 5y ago
So, the car in front was able to swerve, but from 2 cars back, he couldn’t and ended up killing a person. Somebody wasn’t paying attention. Not they he’s unique in this, but his statement is baloney.
- TeeWEE 5y ago
  Even at a save distance, if the car was at a complete standstill, thats something completely unexpected on the highway. Having to react in such a short timeframe is close to impossible for a human, even when you keep a "safe distance" The "safe distance" is only "safe" if all the traffic is moving at least.
  - notreallyserio 5y ago
    I've seen cars at a complete standstill on the highway more than once. It's fair to say it is unusual but it should be fully expected, IMO. I don't understand the scare quotes around safe distance here. Maintaining safe distance (and the implied safe speed and open eyes) absolutely would help in these situations.
- Aeolun 5y ago
  Car in front saw the car before them suddenly start to brake, but Tesla was still moving fast enough to get out of the way. Which revealed an almost stationary car to the person behind, whom was still driving 70mph. I can see how that is hard to react to. I wasn’t sure how hard though, so I did a thought experiment. Say there is 50m between each car, and they’re all driving 25m/s. First car starts braking at 5ms. After one second the distance between 1 and 2 is 45m. After two seconds, 35m. After 3s, 20m, and the car is evading. After 4s, car 2 is passing by 1, whom is now moving at only 5m/s. Car 1 is finally revealed to car 3, who now has a maximum of two seconds to do something before it crosses the 50m gap. And that’s assuming an adequate gap. They were likely closer.
- rootusrootus 5y ago
  Have you ever had someone in front of you swerve out of the way, leaving you facing a stopped car? It's exciting, let me tell you. The idea of safe following distance is predicated on the car in front of you not being able to defy physics when they stop, presumably their braking power is similar to yours.
jeofken 5y ago
> If a Model 3 decides to emergency brake without warning, can the driver still steer it to the shoulder of the highway, or are steering commands from the driver ignored? Yes - a slight nudge on the pedals or steering wheel will deactivate autopilot and let you drive like normal.
- FireBeyond 5y ago
  After you've spent another second (and 150 feet) fighting the AP to say, "no, I'm not drifting out of my lane, this is intentional".
  - iso1631 5y ago
    150 feet a second? Where are you driving where you're doing that speed and changing lanes and are concerned about 150 feet? Why doesn't the lane detection deactivate when you indicate?
    - FireBeyond 5y ago
      Sure, maybe 100f/s.
foxyv 5y ago
> He said the car in front of him almost hit the car so they swerved barely missing him and then there was the Tesla right there . This is how my friend lost all 4 wheels on his car. Following too close to react to stuff that the vehicle in front of him could. Hit the raised island for a slip lane when someone swerved out of the right turn lane at the last minute.

by dhx 5y ago

staktrace 5y ago

To reply to your first question: if the car decides to emergency brake, you can still override it by pressing the accelerator. In my experience, the braking that happens is "hard" but no more hard than you would do yourself if something suddenly appeared in your drive path, and if you are paying attention you can press the accelerator within a second or so. If the person behind you has adequate following distance it shouldn't be a problem. If the car loses power entirely then it gives you a few seconds warning in which you may or may not be able to cross to the shoulder before the car coasts to a stop. In this scenario the braking is not "hard", but obviously there is no real way to recover and you'll need to get towed. I have not experienced any scenario where the car does not respond to steering or acceleration commands when it was physically able to do so.

staktrace 5y ago
Self-reply to add: despite (occasionally) experiencing phantom braking and my wife once experiencing the "loss of power" scenario due to a defective drive unit, I'm still very happy with the Tesla overall. In my experience it is the best car I've owned despite the flaws that seem to disproportionately make the headlines.
mysterydip 5y ago
if it emergency brakes, does steering still work or not until you accelerate?
- jeofken 5y ago
  Yes - a slight nudge on the steering wheel or pedals deactivates autopilot. You always have full control like when driving like normal. One should therefore always have the hands on the wheel and feet by the pedals and be ready to drive.
  - rootusrootus 5y ago
    > slight nudge To clarify, this only applies if the car doesn't think you're about to exit the lane. It will momentarily fight you, and it will take more than a slight nudge to override it.
- staktrace 5y ago
  It does work, yes.
mellavora 5y ago
> if something suddenly appeared in your drive path, and if you are paying attention you can press the accelerator within a second or so. So if something appears in your path, the right course of action is to accelerate into it? within a second or so is great but not if you have 1/4 second time to respond. > If the person behind you has adequate following distance it shouldn't be a problem. Nice assumption. > If the car loses power entirely then it gives you a few seconds warning in which you may or may not be able to cross to the shoulder before the car coasts to a stop. may or may not indeed.
- vladvasiliu 5y ago
  > So if something appears in your path, the right course of action is to accelerate into it? Not into it, but around it – if possible, of course. It's something you learn in motorcycle school, for example. The idea is that a motorcycle is harder to maneuver while under hard braking, so you have a better chance of avoiding the obstacle or falling by going around it. >> If the person behind you has adequate following distance it shouldn't be a problem. > Nice assumption. Of course. This also feeds into the above. As in, not only do you have to stop, but also to make sure that the person following you will stop without hitting you.
- jazzyjackson 5y ago
  > So if something appears in your path, the right course of action is to accelerate into it? >> ...the braking that happens is "hard" but no more hard than you would do yourself if something suddenly appeared in your drive path... parent post was just giving a comparison to the deceleration-snap experienced during phantom braking, and saying in the event of a phantom brake, you can cancel the event by tapping the gas (battery?) pedal
- deleted 5y ago
  [deleted]
- staktrace 5y ago
  > So if something appears in your path, the right course of action is to accelerate into it? You mis-parsed what I said here. My sentence was probably too long. Let me try using shorter ones. Say you are driving. Suddenly a squirrel appears on the road 50m away. You apply brakes "hard" to avoid hitting it. This amount of braking is what the car does. You can still press the accelerator. The accelerator works as expected, cancelling the software's braking. > if you have 1/4 second time to respond. Under what circumstances would you have this short amount of time? IMO only if somebody is following you too closely. Again, remove the software from the equation and insert the aforementioned squirrel. You brake hard for it. The person behind rear-ends you because they were following too closely. Who is at fault? > Nice assumption Thank you

rileymat2 5y ago

> He said the car in front of him almost hit the car so they swerved barely missing him and then there was the Tesla right there. This is not a criticism of the driver, because everyone does it, but one of my pet peeves is hardly anyone follows at a safe distance. Most of the time you can’t even if you want to because someone will merge in front of you with that much space.

Iolaum 5y ago
So true!
dahfizz 5y ago
> Most of the time you can’t even if you want to because someone will merge in front of you with that much space. This annoys me so much. It creates a game theory situation where everybody has to drive like an asshole in order to avoid being cut off by assholes.
- mattcwilson 5y ago
  Seems like the game theory being applied there is a bit of prisoners dilemma. Is playing “asshole” the right move?
  - pclmulqdq 5y ago
    In California, unfortunately, the answer seems to be "yes." When I moved to the northeast US, drivers were more sane on highways.
    - tfigment 5y ago
      When I moved to Boston, the first lesson I learned was any gap in front of me that can fit a car will soon have one there. I think it is big cities in general not just regions.
      - lotsofpulp 5y ago

iso1631 5y ago

> He absolutely could not of stopped in time. Somebody (not necessarily the husband) was driving too close to the car in front. You should have enough time to see the car stopping and stop yourself. A 2 second gap at 60mph is 178 feet. A second to react and that still gives you 88 feet to slow down in before you even get to the point where the Tesla started to slow, reducing the impact speed to far lower -- not enough that should kill anyone.

jazzyjackson 5y ago
crowded expressways have a way of filling gaps
reallydontask 5y ago
Not necessarily the case. Friend of mine was on the middle lane on the motorway when somebody switched on to his lane and braked hard. He crashed against but wasn't deemed at fault by insurance. Not saying that this is what happened, btw.

alistairSH 5y ago

So, the car in front was able to swerve, but from 2 cars back, he couldn’t and ended up killing a person. Somebody wasn’t paying attention. Not they he’s unique in this, but his statement is baloney.

TeeWEE 5y ago
Even at a save distance, if the car was at a complete standstill, thats something completely unexpected on the highway. Having to react in such a short timeframe is close to impossible for a human, even when you keep a "safe distance" The "safe distance" is only "safe" if all the traffic is moving at least.
- notreallyserio 5y ago
  I've seen cars at a complete standstill on the highway more than once. It's fair to say it is unusual but it should be fully expected, IMO. I don't understand the scare quotes around safe distance here. Maintaining safe distance (and the implied safe speed and open eyes) absolutely would help in these situations.
Aeolun 5y ago
Car in front saw the car before them suddenly start to brake, but Tesla was still moving fast enough to get out of the way. Which revealed an almost stationary car to the person behind, whom was still driving 70mph. I can see how that is hard to react to. I wasn’t sure how hard though, so I did a thought experiment. Say there is 50m between each car, and they’re all driving 25m/s. First car starts braking at 5ms. After one second the distance between 1 and 2 is 45m. After two seconds, 35m. After 3s, 20m, and the car is evading. After 4s, car 2 is passing by 1, whom is now moving at only 5m/s. Car 1 is finally revealed to car 3, who now has a maximum of two seconds to do something before it crosses the 50m gap. And that’s assuming an adequate gap. They were likely closer.
rootusrootus 5y ago
Have you ever had someone in front of you swerve out of the way, leaving you facing a stopped car? It's exciting, let me tell you. The idea of safe following distance is predicated on the car in front of you not being able to defy physics when they stop, presumably their braking power is similar to yours.

jeofken 5y ago

> If a Model 3 decides to emergency brake without warning, can the driver still steer it to the shoulder of the highway, or are steering commands from the driver ignored? Yes - a slight nudge on the pedals or steering wheel will deactivate autopilot and let you drive like normal.

FireBeyond 5y ago
After you've spent another second (and 150 feet) fighting the AP to say, "no, I'm not drifting out of my lane, this is intentional".
- iso1631 5y ago
  150 feet a second? Where are you driving where you're doing that speed and changing lanes and are concerned about 150 feet? Why doesn't the lane detection deactivate when you indicate?
  - FireBeyond 5y ago
    Sure, maybe 100f/s.

foxyv 5y ago

> He said the car in front of him almost hit the car so they swerved barely missing him and then there was the Tesla right there . This is how my friend lost all 4 wheels on his car. Following too close to react to stuff that the vehicle in front of him could. Hit the raised island for a slip lane when someone swerved out of the right turn lane at the last minute.