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WARNING: I rear-ended someone today while using Auto Pilot in my brand new P90D!

CharlesMW

Member
Oct 16, 2015
14
1
Chevy Chase, MD
In my Volvo XC-60 with City Safety (Volvo Emergency Stopping system), If you even touch the brake slightly with your foot - the car DOES NOT engage city safety as it assumes you are in control. - This may be the same case with Tesla Self Stopping ??
 

DCGOO

Active Member
Nov 24, 2015
1,708
1,000
Indianapolis, IN
Thanks. I completely agree. I initially hesitated to even post about my accident, but I felt kind of a moral duty. Hopefully, if there is a legitimate problem, it can be fixed, and I can post only about how much I love my P90D.

To calisnows point, there was a review of the P90DL in a recent PBS Motorweek episode. The distance to stop from 60 MPH was 110 feet... and that was with a professional driver. The opinion of the reporter was "Excellent performance." Were you back 110 feet (hopefully more like 200 feet) when you attempted to stop? I am guessing not. If you weren't, you are not going to make that 5,000 lb machine stop. Set the following distance to 6 or 7 and even then, hover over the brake in traffic. AP is great. But it is not THAT good.
 

Todd Burch

Voltage makes me tingle.
Nov 3, 2009
8,263
34,184
Smithfield, VA
Sorry to hear about this. A few comments from my perspective:

1. Automatic Emergency Braking is intended to avoid a serious collision. It will not engage if you're only going 5-10 mph or so. Someone else accidentally let their car roll forward into the garage wall (admitted they were at fault) but afterward questioned why AEB didn't stop the car. It's not supposed to in this situation--only if there is a large speed differential between the car and an obstacle on a collision course.

2. I've never had anything like this happen to me--I've never seen an issue like this with TACC, and I use it on surface streets and highways about 200 miles a week. But you have to be aware of the limitations. I'd suggest that 2 car lengths is really too close. I leave my distance setting on 7, but I suggest at least 5.

3. For other new owners, I suggest using autopilot with hands on the wheel and foot covering the brake, paying very close attention, for the first several hundred miles of use. Watch what it does, where it can get confused, etc. Then as you start noticing that you can anticipate how it will behave, you can relax--just a little bit.
 

CHG-ON

Still in love after all these miles
Jun 24, 2014
3,079
648
Santa Cruz Mountains, USA
I think people are being overly critical of Sandstruck here.

Yes. I completely agree that we need to be in control at all times, without exception. No excuses. I don't see Sandstruck making any excuses at all. He/she is taking full responsibility. But the general concept behind TACC, and Auto Steer, for that matter, is that the car will accelerate and decelerate, according to the conditions, in a manner adequate to stop the vehicle, along with steer, etc. That, along with emergency braking, should work well enough to avoid this situation.

Do I trust it? No way. But I can easily see how this could happen. Regardless of what Tesla says about our being responsible, blah, blah, if their system cannot avoid running into the car in front of it when the car gradually slows (assuming Sandstruck is correct), then they will be in for a heap of trouble either legally or through loss of demand for the product because it is ineffective.

I have had a concern that Tesla is rolling out these updates like SW developers do, with the general attitude that if it doesn't work, they will simply update it in the next rev. My concern is that these are not computers, phones, etc. These are cars that can kill people rather quickly.

Yes, they say that we must be in control at all times and we should. But the expectation among the users is that it actually does work.

I'm saddened by this event but am glad that all are OK and that nothing more than a fender bender came of it.
 

sandstruck

Member
Nov 24, 2012
40
0
chicago
Sorry to hear about this. A few comments from my perspective:

1. Automatic Emergency Braking is intended to avoid a serious collision. It will not engage if you're only going 5-10 mph or so. Someone else accidentally let their car roll forward into the garage wall (admitted they were at fault) but afterward questioned why AEB didn't stop the car. It's not supposed to in this situation--only if there is a large speed differential between the car and an obstacle on a collision course.

2. I've never had anything like this happen to me--I've never seen an issue like this with TACC, and I use it on surface streets and highways about 200 miles a week. But you have to be aware of the limitations. I'd suggest that 2 car lengths is really too close. I leave my distance setting on 7, but I suggest at least 5.

3. For other new owners, I suggest using autopilot with hands on the wheel and foot covering the brake, paying very close attention, for the first several hundred miles of use. Watch what it does, where it can get confused, etc. Then as you start noticing that you can anticipate how it will behave, you can relax--just a little bit.

This is sage advice. It was definitely a bad idea to set my distance at 2 for highway driving. I was too cavalier, too starstruck and trusting of the technology. It simply never ocurred to me that the car would fail to stop. That was foolish.
 

Julian Cox

Banned
Jul 17, 2013
1,313
1,613
Cox
Elon mentioned that there had been one or two incidents in which a driver thought that AP was on but it was not. This being one of those would seem to be a most plausible explanation. I can imagine even an experienced driver's foot wandering across the brake pedal of an unfamiliar car and not necessarily appreciating that he had actually knocked his car out of TACC mode.

That said, the possibility of inadvertently knocking a car out of AP or TACC is a relatively novel form of driver's error that is worth thinking about. When Elon tweeted for 7.1 feature suggestions, one of them that was submitted (by me) was to consider that knocking the steering wheel should perhaps have some mode of default behavior to resume auto steer rather than to cancel it altogether - for example if the contact with the steering wheel is only momentary. That could be momentary enough to correct AP behavior or it could be momentary like turning around to check on a rear seat passenger and hitting the wheel with an elbow. Either way resuming AP would probably be the better idea than dropping out of Auto Steer altogether. TACC, not so sure - but maybe a brief touch on the brake pedal should disengage cruise while maintaining TACC distance-keeping instead of falling back all the way to AEB - and a more decisive press should drop out of TACC altogether. This would improve upon classic TACC behavior I think.

It is not necessarily the case here that emergency braking was not standing on the brakes at the same time as the driver assuming it was the case that the driver had mentally abdicated responsibility for detecting stationary traffic before it became a legitimate emergency braking exercise detected by both car and driver simultaneously. With TACC and even ordinary Cruise Control usually you kinda know if you stepped on the brake to disengage it. There is nothing novel in the case of a Tesla about a car that disengages these features with the brake pedal (or the stalks/buttons) without intrusive warning fanfare to say that it has in fact disengaged.

Never cool to scratch a new car but the logs are where the answer is at.
 
Last edited:

green1

Active Member
Mar 25, 2014
4,548
1,495
Calgary, Alberta, Canada
AEB is not designed to avoid collisions, only reduce the impact. OP said it made noise before the crash, so it seems to have worked as designed. AEB works between 5 and 85mph and will only reduce your speed by a maximum of 25mph before it disengages (this is all in the manual) Due to the low amount of damage to the vehicle, it looks like it was quite likely down to 5mph at time of impact. AEB success!

As for "taking responsibility" I contend that the OP is not taking responsibility because they continue to state that there is nothing they could have done to avoid the collision. That is patently false, and is not taking full responsibility.
 

Plan B

Active Member
May 8, 2015
4,911
2,564
Portland OR
This is sage advice. It was definitely a bad idea to set my distance at 2 for highway driving. I was too cavalier, too starstruck and trusting of the technology. It simply never ocurred to me that the car would fail to stop. That was foolish.

Don't beat yourself up so much, **** happens...it's only a car and no one got hurt.
 

sandstruck

Member
Nov 24, 2012
40
0
chicago
AEB is not designed to avoid collisions, only reduce the impact. OP said it made noise before the crash, so it seems to have worked as designed. AEB works between 5 and 85mph and will only reduce your speed by a maximum of 25mph before it disengages (this is all in the manual) Due to the low amount of damage to the vehicle, it looks like it was quite likely down to 5mph at time of impact. AEB success!

As for "taking responsibility" I contend that the OP is not taking responsibility because they continue to state that there is nothing they could have done to avoid the collision. That is patently false, and is not taking full responsibility.

i see your point. I think i was trying to say that i couldn't do anything ONCE i realized the car wouldn't stop. If i had used more caution (and more distance/time), it sounds probable I'd have avoided the accident. Had i had read something like this string (i haven't perused this site since 2013) or had my DS (or anyone else) advised me to be more judicious, perhaps i wouldn't have collided. I'm not trying to abdicate responsibility (and i know i lack some common sense here) but I'm just suggesting that it couldn't hurt for the DSs to advise customers of these potential pitfalls
 

gizmoboy

Member
Jul 2, 2015
701
41
Rancho Palos Verdes, CA
I'm fully with you on the AP thing and rather concentrate on the stuff that actually is part of their mission statement.
My car is AP-capable but no way in hell am I going to enable it.

I have no problem taking responsibility for my driving, but I want full control over my car.

What do you think about power steering? Power brakes? Drive by wire? Cruise control? TACC?

Where does the line between "I have full control over my car" get crossed for you?
 
Nov 2, 2015
60
3
Santa Barbara, CA
OP, Thank you for for posting about this problem.

I just got back from a quick 2-day round-trip drive to San Francisco (~700 miles), where I used the AP frequently. SF has the most horrible traffic. At speeds below 25 mph, I had the setting at 2-car distance (yes, Tesla calls it 2-car distance), and increased it at higher speeds, up to 7 at 65 mph or higher. Worked like a charm.

But, I kept wondering how the car would have reacted if the car in front of me just slammed the brakes all of a sudden. I had no trust that the AP would've reacted better than I could (in my most alert state), and this is based on my observations of the AP behavior in 2 hr bumper-to-bumper traffic. However, it would certainly minimize any fallout that could have resulted in a fender-bender if someone was distracted. Thus, the AP (7.0) can be viewed as a very good back-up system (NOT a self-driving feature).

Now, 2 hrs ago, while driving back home, I got a message about the upgrade to v 7.1. Should I do it?
 

Todd Burch

Voltage makes me tingle.
Nov 3, 2009
8,263
34,184
Smithfield, VA
Sandstruck, I'll also add that it takes a lot of courage to not only share a story like this, but also to accept blame for it, so I commend you for that.

There are two possibilities that I can think of that may have been the cause for this.

1) In general, the radar filters out stationary objects--otherwise the radar would be going haywire passing signs, stopped cars on the side of the road, traffic cones, barriers, etc. In general I've found the radar to be good at recognizing stopped cars in traffic ahead and as I mentioned in an earlier post have never had a situation where TACC didn't see a stopped car ahead--but as a general rule it's a good idea to assume the radar won't see anything stationary. In other words, if TACC is engaged and you're coming up on a block of stopped traffic, get ready to brake. (Personally, TACC brakes a bit harder than I would, so I tend to disengage it when approaching stopped traffic to regen at my own rate).

It's possible in this case that with a car changing lanes ahead, the radar was tracking the car changing lanes but didn't have enough time to lock on a stationary car further ahead.

2) No offense, but it's also possible that you either accidentally disengaged TACC or misinterpreted something. After all, although you're not new to the S you are new to the autopilot features. The logs should help clear up any questions.

- - - Updated - - -

But, I kept wondering how the car would have reacted if the car in front of me just slammed the brakes all of a sudden. I had no trust that the AP would've reacted better than I could (in my most alert state), and this is based on my observations of the AP behavior in 2 hr bumper-to-bumper traffic.

That happened to me. I was following a car with TACC engaged and the car in front slammed on his brakes. I wasn't in immediate danger of a collision because my following distance was somewhere in the 5-7 range at the time, but the TACC reacted instantly...much faster than the half second or so reaction time that I had, even though I was alert.

I think hands down TACC will beat any human reaction time. As I recall it's operating somewhere in the 60-120 Hz range...so can react on the order of about 10-20 milliseconds. Human reaction time is an order of magnitude larger than that.
 

msnow

Active Member
Jul 14, 2015
4,951
2,394
SoCal
OP, Thank you for for posting about this problem.

I just got back from a quick 2-day round-trip drive to San Francisco (~700 miles), where I used the AP frequently. SF has the most horrible traffic. At speeds below 25 mph, I had the setting at 2-car distance (yes, Tesla calls it 2-car distance), and increased it at higher speeds, up to 7 at 65 mph or higher. Worked like a charm.

But, I kept wondering how the car would have reacted if the car in front of me just slammed the brakes all of a sudden. I had no trust that the AP would've reacted better than I could (in my most alert state), and this is based on my observations of the AP behavior in 2 hr bumper-to-bumper traffic. However, it would certainly minimize any fallout that could have resulted in a fender-bender if someone was distracted. Thus, the AP (7.0) can be viewed as a very good back-up system (NOT a self-driving feature).

Now, 2 hrs ago, while driving back home, I got a message about the upgrade to v 7.1. Should I do it?

Yes, absolutely!
 

ecarfan

Well-Known Member
Sep 21, 2013
19,458
14,465
West Vancouver, British Columbia
That is entirely your opinion. I run TACC\AP at 2 car lengths all the time unless the pavement is wet then I change it to 4 and to date, I have not had an issue with those distances.
I am glad you have not had an accident using TACC at the 2 setting at highway/freeway speeds (the specific scenario I described as "unsafe"). My experience with TACC set at 2 is that the distance it maintains is far less than what is required when reacting and then braking in response to the car in front doing maximum emergency braking at highway/freeway speeds, even on a dry road.
Just because TACC lets you set a distance of 2 or 1 at high speeds doesn't mean that is a safe setting.
 

brec

Member
Aug 3, 2015
363
140
Reno & Las Vegas, NV
If it sounds implausible, it probably is. This means TACC failed. Not AP. And that is very unlikely to happen.
(Cross-post of a reply of mine at teslamotors.com)

As to terminology, here is Tesla's:

Autopilot, which includes:

--Autosteer

--Autopark
----parallel
----perpendicular
----Summon

--Traffic-Aware Cruise Control (TACC)

The hierarchical levels are as indicated in the 7.1 Release Notes.
 

msnow

Active Member
Jul 14, 2015
4,951
2,394
SoCal
@brec, I'm not clear on your point. The OP's subject said he was using AP and the person you quoted was pointing out the specific component.
 

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