Unintended Accleration

[AnxietyRanger]

I tried to activate my AP2 cruise while making a left turn but unsuccessful for quite a few times as it complained something like "TACC not available".

However, I finally could set it at 40 MPH while doing a left turn at the speed of 20 MPH and I did not lose control of the car at all.

(The grey circle on top left of instrument cluster was 18 then automatically changed to 40 then it's lit up in teal color as I pulled the cruise control stalk toward me once.)

I am not sure what is your point.

Obviously this can happen when the minimum CC set speed limit is exceeded:

1) You are approaching a right-hand turn
2) Lift the throttle, the car starts slowing down for the turn
3) Flick the CC stalk upwards thinking to indicate a right-hand turn, but instead of enabling CC at speed
4) Turn the corner while assuming the car slows down
5) Enter the corner - and come out of it - at a steady speed, instead of a slowing down speed

Whether you can maintain control depends obviously completely on the corner, the weather (rain, snow, ice) and what comes right after it. The problem is the same, though: you are assuming a continuously slowing down car (single-pedal driving, remember), instead of one that keeps a steady speed.

This can happen also on left-hand turns, but mistakenly hitting the CC stalk instead of the blinker seems less likely due to the direction your hands are moving.

 

[modamoda]

"street is marked at 30mph" that reminds me something.

it's more like an edge case, but sometimes Tesla cannot recognize speed limit sign correctly. I saw someone's youtube video - Autopilot-ing Model S recognized speed limit sign 80 as 30, so the car started to decrease speed. your case is opposite case: recognize number 30 as 80.

Well it's just my hypothesis tho

 

[rush6410]

Yes, this is correct, but this is also the problem - especially in a single-pedal driving scenario.

Consider this:

1) You are approaching a right-hand turn
2) Lift the throttle, the car starts slowing down for the turn
3) Flick the blinker stalk upwards to indicate a right-hand turn
4) Turn the corner while the car slows down
5) Accelerate only after turning the corner

Now, replace 3) with an accidental flick of the cruise control stalk upwards (which can happen especially with right-hand turns because CC is the first stalk where hand movements turning right might hit it first)... where the car enters the corner at a steady speed, instead of continuously slowing down which you are assuming it would do....

Hence the problem. There are many threads like this one on TMC.

I do not know about HW1 vehicles. But, HW2 vehicles will slow down in a turn with TACC set. I have entered a hard turn (Left or Right 90 degree) with TACC set. Without pushing the break the vehicle slowed to around 5mph through the hard turn. Then, the vehicle sped back up to TACC set speed, 45mph. So, this might be an improvement with HW2.

 

[DarkMatter]

And if you have the room in the friction circle to slow through the turn, you had the room to accelerate.

 

[Tam]

...I am not sure what is your point...

My point is: current setup is safe and convenient to use even if I activate cruise control set at a very high speed of 40 MPH during a very tight turn.

Since it is convenient and safe, there's no need to implement prior car Prius' 2 step cruise control procedure.

 

[BerTX]

My point is: current setup is safe and convenient to use even if I activate cruise control set at a very high speed of 40 MPH during a very tight turn.

Since it is convenient and safe, there's no need to implement prior car Prius' 2 step cruise control procedure.

Did you test it with a car making the same turn in front of you? Or with a car coming around the turn from the opposite direction? Or in the rain? Ice, snow? With a less competent driver than you?

 

[AnxietyRanger]

My point is: current setup is safe and convenient to use even if I activate cruise control set at a very high speed of 40 MPH during a very tight turn.

Since it is convenient and safe, there's no need to implement prior car Prius' 2 step cruise control procedure.

I have a hard time seeing how a single example of driving a corner would be proof of that.

Going into a corner at a speed and speed change rate you are not expecting or planning can IMO obviously be dangerous.

For example, if you progressively expect the car to be slowing down and it keeps going at a steady speed instead, anything surprising after the turn can easily be disastrous...

 

[BerTX]

I have a hard time seeing how a single example of driving a corner would be proof of that.

Going into a corner at a speed and speed change rate you are not expecting or planning can IMO obviously be dangerous.

For example, if you progressively expect the car to be slowing down and it keeps going at a steady speed instead, anything surprising after the turn can easily be disastrous...

Might be even more dangerous with one-pedal driving. All our lives we have gone around tight corners with our foot on the brake, and if something unexpected happens, we hit the brake. Now we have our foot on the accelerator with regen doing the braking.. Probably the same wiring in our brain to press down on the pedal in case of emergency = "unintended acceleration".

 

[DarkMatter]

Braking in a turn isn't always the best choice. If you plan to drive in situations with that little margin, be careful with the car controls.

 

[AnxietyRanger]

Braking in a turn isn't always the best choice. If you plan to drive in situations with that little margin, be careful with the car controls.

True as that may be, I know what is never the best choice: car doing something you did not intend to happen (even if it does it by your "command" but one that you did not realize giving).

If there are usability improvements that could be made to avoid confusing the CC stalk to blinker and setting cruise on at present speed accidentally when turning, IMO those improvements would be welcome.

 

[DarkMatter]

And I would say that adding steps to control operation is a headache. You don't have to double-tap the accelerator to start the car moving.

 

[AnxietyRanger]

And I would say that adding steps to control operation is a headache. You don't have to double-tap the accelerator to start the car moving.

I am not suggesting adding steps.

I am suggesting usability improvements that also lessen mistake risks. For example, does the car have to set CC from an upwards flick. Maybe it could only do it downwards, that would remove the most obvious issue (the right-hand turn blinker). Or maybe it could require a slightly longer flick of the stalk to enable CC (like it does for Autopilot)... or maybe Tesla could bring back the button at the end of the stalk and use that instead...

Or maybe someone smarter than me can come up with an even better way...

 

[DarkMatter]

If I am remembering correctly it only sets on a full up or down, which has two detents. It's really quite different than the turn signal.

 

[AnxietyRanger]

If I am remembering correctly it only sets on a full up or down, which has two detents. It's really quite different than the turn signal.

All I'm saying is that these threads are numerous by now. It suggests to me this could use some looking into - maybe all it would take would be quite subtle changes...

 

[Krazaak]

I am not sure what is your point.

Obviously this can happen when the minimum CC set speed limit is exceeded:

1) You are approaching a right-hand turn
2) Lift the throttle, the car starts slowing down for the turn
3) Flick the CC stalk upwards thinking to indicate a right-hand turn, but instead of enabling CC at speed
4) Turn the corner while assuming the car slows down
5) Enter the corner - and come out of it - at a steady speed, instead of a slowing down speed

Whether you can maintain control depends obviously completely on the corner, the weather (rain, snow, ice) and what comes right after it. The problem is the same, though: you are assuming a continuously slowing down car (single-pedal driving, remember), instead of one that keeps a steady speed.

This can happen also on left-hand turns, but mistakenly hitting the CC stalk instead of the blinker seems less likely due to the direction your hands are moving.

My BMW activated cruise by pushing up on the stalk as well and was situated similarly to the Tesla. I'm having a hard time seeing the danger with this though...

1) 100 ft before your right-hand turn, signal.
2) Whoops, turned on CC and I can immediately feel that regenerative braking cancelled.
3) Turn off CC.

 

[AnxietyRanger]

My BMW activated cruise by pushing up on the stalk as well and was situated similarly to the Tesla. I'm having a hard time seeing the danger with this though...

1) 100 ft before your right-hand turn, signal.
2) Whoops, turned on CC and I can immediately feel that regenerative braking cancelled.
3) Turn off CC.

Do it late in the turn and the scenario becomes different. Do it as you turn, it can become very dangerous.

Not all realize what is happening until it is late. At least one person crashed on TMC not realizing CC had (likely) enabled. And this very thread documented a close call...

If usability improvements could mitigate this, I think it would be worth it.

 

[Krazaak]

Do it late in the turn and the scenario becomes different. Do it as you turn, it can become very dangerous.

Not all realize what is happening until it is late. At least one person crashed on TMC not realizing CC had (likely) enabled. And this very thread documented a close call...

If usability improvements could mitigate this, I think it would be worth it.

I'd argue that turning on your turn signal late in your turn or right before your turn is already a problem.

You shouldn't be braking during a turn anyway under normal circumstances. Brake before your turn, maintain speed through the turn and accelerate out of it. I was coming from a BMW X6M though with torque vectoring, so I was usually downshifting to engine brake before a turn and accelerating through it to shift torque to the outside wheels and push through the turn.

I need to check exactly how the CC stalk behaves. I would agree with you that pushing the stalk up is a problem if it resumes the set speed for CC, but if it behaves like my BMW, which simply sets CC at the current speed; then I don't really see the danger.

If you're taking a corner so fast that maintaining your current speed for the few seconds it takes you to realize you've enabled CC causes you to lose control, then you were taking the corner too fast in the first place.

 

[DarkMatter]

Read my earlier post to see the current behavior.

 

[Ulmo]

Might be even more dangerous with one-pedal driving. All our lives we have gone around tight corners with our foot on the brake, and if something unexpected happens, we hit the brake. Now we have our foot on the accelerator with regen doing the braking.. Probably the same wiring in our brain to press down on the pedal in case of emergency = "unintended acceleration".

I noticed this when I had a Model S and programmed myself into a new practice: whenever I took my foot off the accel, I moved it over to the brake. I also cognated that it was over whichever pedal it was over. I also sometimes brought out my left foot to hover over the brake just so I had mental physical awareness of the situation. I think I slowly improved upon that, but I forget the details now. But I know key to my policy was to have a physical mental awareness by placing feet in such a manner that I had some physical nerve intuition there.

(Mountain driving freeways and highways with lots of commute traffic)

 

[Krazaak]

Read my earlier post to see the current behavior.

Yeah, saw that after I posted and tested while I was out. I don't see anything wrong with the current behavior unless you're driving unsafely to begin with.

I noticed this when I had a Model S and programmed myself into a new practice: whenever I took my foot off the accel, I moved it over to the brake. I also cognated that it was over whichever pedal it was over. I also sometimes brought out my left foot to hover over the brake just so I had mental physical awareness of the situation. I think I slowly improved upon that, but I forget the details now. But I know key to my policy was to have a physical mental awareness by placing feet in such a manner that I had some physical nerve intuition there.

(Mountain driving freeways and highways with lots of commute traffic)

I think it was less disorienting coming from an automatic with heavy engine braking and a manual. The regenerative braking isn't that much different.