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Sudden Acceleration - NHTSA
- Thread starter jfinephilly
- Start date
AlanSubie4Life
Efficiency Obsessed Member
Probably a good idea. Every single safety organization (weather service, highway patrol, etc.) continue to recommend not using cruise control in the rain. In spite of this poorly headlined clickbait Jalopnik article, it's very likely a bad idea to use it in poor conditions (as the article says!).
Let's Debunk The Idea That It's Not Safe To Use Cruise Control In The Rain
The main reason is that it can lead to loss of situational awareness and you will likely end up traveling faster in unsafe conditions than you would be traveling if the accelerator was under human control.
Anyway, back to unintended acceleration...
ElectricIAC
Good-Natured Rascal
I just drive whatever feels comfortable when not on AP.
I had something happen yesterday that I could imagine happening to others, and while it didn't end in any problems for me it was startling for sure. I have thought about it, and I'm pretty sure it can be explained as not a 'bug' or car failure, but it might be an instance of bad design and something that I think Tesla could do a better job with that might increase confidence.
Here's what happened:
Small 2 lane city street, approached a stop light. Hold Mode on, came to a complete stop, second car at light.
I was picking up my wife at the corner, so she hopped in the car.
Light changed a little before my wife got the door closed, so the car ahead of me pulled away.
Once she was in I stepped on the accelerator, car accelerated as normal, and I caught up to the car in front of me we were moving maybe 20-25 mph.
Proceeded for about 2 blocks, red light ahead.
Took foot off accelerator to slow down, car slowed for a second as regen kicked in, and then started to speed up, not a ton, but maybe 5 mph.
I was already moving foot to brake and as soon as I hit the brake everything behaved as you would expect. I'm 100% sure I wasn't pushing the accelerator. ( I know everyone says that...)
As I looked over at the display, I could see the blue ring around the TACC set speed animating off.
In retrospect what I'm pretty sure happened is that back when I stopped for my wife to get in the car, I didn't switch into park, just brake hold, and then once the door was closed and she was in, I shifted the car into 'drive'. No effect at the moment because of brake hold, but I was really driving with TACC on without realizing it.
I don't know about you, but I've had moments where I've overridden auto steer via the wheel and TACC stays on, which is standard behavior, but not always obvious. I think TACC being on could be a lot less subtle, and the overlap between the control to turn on TACC and put the car into Drive is a little close for comfort from my perspective. The expected behavior on TACC when you are stopped with brake hold on... I'm not sure I'd agree with the decision of 'turn it on, but wait until the user hits the accelerator to start driving for the first time." Seems like something that could be an invisible decision that might surprise people in unpleasant ways. Especially if you are switching between reverse/drive start/stop a bunch in a parking lot or somewhere.
Here's what happened:
Small 2 lane city street, approached a stop light. Hold Mode on, came to a complete stop, second car at light.
I was picking up my wife at the corner, so she hopped in the car.
Light changed a little before my wife got the door closed, so the car ahead of me pulled away.
Once she was in I stepped on the accelerator, car accelerated as normal, and I caught up to the car in front of me we were moving maybe 20-25 mph.
Proceeded for about 2 blocks, red light ahead.
Took foot off accelerator to slow down, car slowed for a second as regen kicked in, and then started to speed up, not a ton, but maybe 5 mph.
I was already moving foot to brake and as soon as I hit the brake everything behaved as you would expect. I'm 100% sure I wasn't pushing the accelerator. ( I know everyone says that...)
As I looked over at the display, I could see the blue ring around the TACC set speed animating off.
In retrospect what I'm pretty sure happened is that back when I stopped for my wife to get in the car, I didn't switch into park, just brake hold, and then once the door was closed and she was in, I shifted the car into 'drive'. No effect at the moment because of brake hold, but I was really driving with TACC on without realizing it.
I don't know about you, but I've had moments where I've overridden auto steer via the wheel and TACC stays on, which is standard behavior, but not always obvious. I think TACC being on could be a lot less subtle, and the overlap between the control to turn on TACC and put the car into Drive is a little close for comfort from my perspective. The expected behavior on TACC when you are stopped with brake hold on... I'm not sure I'd agree with the decision of 'turn it on, but wait until the user hits the accelerator to start driving for the first time." Seems like something that could be an invisible decision that might surprise people in unpleasant ways. Especially if you are switching between reverse/drive start/stop a bunch in a parking lot or somewhere.
AlanSubie4Life
Efficiency Obsessed Member
If that's what happened, there would have been insistent beeping from the car when your wife opened the door, and you probably would have had to unlock the door for her to be able to get in. Do you remember needing to do either of these things?
Certainly there is the possibility of mode confusion when using TACC or coming to a stop after using autopilot, or other situations (like the one you describe) where TACC is still on and you're not aware of it. Also possible to engage it when not intended. I've actually inadvertently tried to go in reverse (cancel Autopilot) when Autopilot was already cancelled on a few occasions (fortunately it seems that there are some interlocks on this since it did not go into reverse, even though I (think) I was going slowly enough). Just good to learn the car and understand all the ways in which mode confusion can occur.
this is my experience with TACC anytime I take over to pass or something. You’re not crazy.
If Unintended Acceleration happened to me, I'd set up a dual-channel dash cam, with the rear channel cam down by the accelerator pedal. The front dash cam would be mounted on the roof glass behind the driver, between the two front seats. That way you could see the center display, etc. My Vava dash cam would be easy to setup this way. I got it around Black Friday for about $100. Works great, and would be perfect for monitoring Unintended Acceleration.
definitely had to unlock the car, or at least I did it before I stopped because I knew I was going to be stopping on the street and wanted to make sure she could get in quickly.
I don’t really remember hitting drive before I started up again but that is the only explanation I can think of. I’m generally suspicious of the idea that I’d want to turn on TACC in this scenario, at a complete stop with brake hold on, but short of another control to disambiguate between gear and autopilot... maybe some sort of chime or display alert when you go into an automated mode but it’s deferred by brake hold. This is the only scenario I can think of where it is waiting to take over for you and you might not be as aware because nothing is happening now.
AlanSubie4Life
Efficiency Obsessed Member
The insistent sharp triple beeping is the thing that would be definitive. If you heard that the car was in drive. You should have only been able to engage TACC if there was a vehicle detected ahead, and it was more than 5 feet ahead of you.
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Same as me and one user in my group .
M3 LR unexpected accelerate while AP and Hold enable ,
for me the car just row and I push brake before hit the car in front.
No clue what happen but I've got M3 just a week .
M3 LR unexpected accelerate while AP and Hold enable ,
for me the car just row and I push brake before hit the car in front.
No clue what happen but I've got M3 just a week .
Yep. Here we go again. This will very likely be exactly the same as every other past claim of the car accelerating on its own .. which is that it was driver error and not a problem with the car.
Fernand
Active Member
I believe that people who are driving an electric car with such enormous and near-instant acceleration and deceleration should pay attention and be ready to react at any time.
The slightest driver error or AP request can move the car a lot more than we were used to, given all the inertia of the old ICE machines in which a lot of driver mini-goofs in accel, braking and steering are smoothed out by the machine's lag.
The EV instant torque is like a magnifying glass for any inadvertent passing touch on the accel pedal. I've gotten my share of "both pedals at once" warnings. But still never any "unintended acceleration".
Maybe one pedal driving, once people get used to this dance, will reduce the incidence of stepping on your pedal partner's toes.
As to "phantom braking" I've seen very rare situations where the AP is uncertain and errs on the side of caution, i.e. slowing to avoid an imagined potential collision. I've seen maybe 3 in the entire year I'm driving the Model 3 in AP/NOA, always in the right lane or by an exit, overpass or a branching. And never "braking", just some slowing to avoid (possible) danger. The driver should be attentive and in control, adding some accel if necessary, IMHO no big deal.
People who worry about these things should perhaps muzzle the car by keeping regen low, initial speed 5 or 10 MPH BELOW posted speed, the "hold" mode off (?), and accel in Chill mode. Anything else?
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The slightest driver error or AP request can move the car a lot more than we were used to, given all the inertia of the old ICE machines in which a lot of driver mini-goofs in accel, braking and steering are smoothed out by the machine's lag.
The EV instant torque is like a magnifying glass for any inadvertent passing touch on the accel pedal. I've gotten my share of "both pedals at once" warnings. But still never any "unintended acceleration".
Maybe one pedal driving, once people get used to this dance, will reduce the incidence of stepping on your pedal partner's toes.
As to "phantom braking" I've seen very rare situations where the AP is uncertain and errs on the side of caution, i.e. slowing to avoid an imagined potential collision. I've seen maybe 3 in the entire year I'm driving the Model 3 in AP/NOA, always in the right lane or by an exit, overpass or a branching. And never "braking", just some slowing to avoid (possible) danger. The driver should be attentive and in control, adding some accel if necessary, IMHO no big deal.
People who worry about these things should perhaps muzzle the car by keeping regen low, initial speed 5 or 10 MPH BELOW posted speed, the "hold" mode off (?), and accel in Chill mode. Anything else?
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I will have to try from brake hold in controlled circumstances. I don’t think there was a rejection of TACC activation. I don’t remember the sequence of events well enough to say if I put the car into drive a second time, just that something unexpectedly accelerated the car at a time when I expected to be slowing down. I assume it was TACC because I saw that flash of blue onscreen before before I hit the brakes I was on the way to anyway.
Pedal confusion is a real thing, and something that causes I think most of the traditional accidents with the classic unexpected acceleration. But in this new semi automated world there is actually a possibility that the car accelerates or brakes in a way the driver doesn’t expect, and isn’t directly linked to a user action like pushing hard on the accelerator. Phantom braking, or a bad speed limit value in the Tesla data can cause the car to do things that no traditional car would ever do.
It was the heaviest snow of the year when this had happened. I’m very sure I switched to chill mode and set regen to low before drive. Before that, it was in hold mode and regen set to standard. And I’m very comfortable driving in “one pedal” mode. The road is less than 1 degree downhill, if not completely flat. What I remember is I almost came to a complete stop when both car met (my foot on brake). I lifted my foot from the brake half way the other car left. Right before I hit the accelerate pedal, it accelerated. I move my foot back to the brake immediately. What’s your theory about this?
My guess is that people either have TACC engaged without realizing it, or the car hits a slick patch & reduces regen to avoid wheel lockup which feels like acceleration (it’s really reduced braking).
Generally, this is because drivers no longer have a good feel of what the car is telling them. The result is that the very predictable response of killing regenerative to recover traction on the drive wheels feels like acceleration to those used to driving an appliance in a cocoon.
Unintended acceleration has a very long history in automotive...the fault has almost never been with the car.
Unintended acceleration has a very long history in automotive...the fault has almost never been with the car.
RedModel3
Member
