[tdees40]

I just ordered a Model S with Autopilot, and as I've been reading the comments on the various Tesla forums, I'm not sure I'm ever going to use it. Some of the stories are honestly terrifying (sudden deceleration on the highway, swerving into other lanes, etc).

[aerovistae]

Absolutely do not use it.

I am one of the biggest Tesla fans out there. I fucking love the company. But Autopilot in its current form is nothing short of dangerous.

I took a test drive in a Model S a couple months ago and enabled Autopilot at the Tesla rep's encouragement while on a straight stretch of route 90 near Boston. We were going 70mph, a safe speed.

The car came to a point where the highway curved, and a slight deceleration is required to navigate the curve correctly.

Little did I know, Autopilot stays at the speed you set and does not alter it as the environment requires, short of not hitting the car in front of you. So of course it tried to take the curve at 70mph and swung out of the lane almost instantly, prompting immediate corrective action from me to avoid a serious accident.

I couldn't believe the Tesla rep hadn't made this clear. I was required to have my hands on the wheel, but the position of my hands doesn't ensure that I'm mentally ready for egregious errors on the car's part and prepared to correct them at a split second's notice at all times.

Operational question mark aside, as an investor I was also astonished that the software was still in such a rudimentary state that it didn't know to slow down on curves. I found this troubling. It was scarcely more advanced than cruise control, to be honest.

It's the one place where I think Elon is really gambling with people's lives as well as his company's credibility, the former being an infinitely worse transgression than the latter.

[timdorr]

That's not true at all. AP (at least HW2 AP in my car) does definitely slow down for curves. This is more apparent on surface roads, which have more extreme curves. My car will slow down ~15MPH on one curve, whereas I would only slow myself ~5MPH. It's definitely a part of the system.

[Cshelton]

Yeah, this is 100% false. I've owned a Tesla for over a year. I take several curves on a daily basis with the speed set to around 82 mph. Going into the curve, the car slows down to about 65 mph, which is the speed every other car on the road takes that curve. It's even stated in the AP documentation and release notes. Go ask other Tesla owners as well. I've never heard of a Tesla being "swung" out of a lane on a curve.

Tesla uses a combination of the visual lanes, cars in front, and an accelerometer, to determine the curve and how much it needs to slow down.

Other than a freak situation last year (not on a curve, it was the hill crest with the white truck crossing the highway), every SINGLE accident has been shown to be the drivers fault with autopilot disengaged. Not a single accident of what you described has happened.

[aerovistae]

I am glad to hear this.

But it is not 100% false that the Tesla I test drove functioned this way. It is, in fact, 100% true. This happened last month.

[avar]

You may however be overestimating how much a car like the S needs to slow down in a turn. It has a really low center of gravity. Maybe it didn't need to slow down at all and you were just being paranoid.

Can you provide a map link to the stretch of road where this happened?

[aerovistae]

I don't think I was being paranoid....I'm generally a very, very fast driver who prefers the inner lane and 85mph+ speeds given the opportunity. I do know the car has amazing handling but it unequivocally started swerving heavily out of the lane at the speed it was traveling at.

It's route 90 between Allston and Back Bay. It looks like a pretty gentle curve so looking at the map certainly makes my description of events seem questionable, but I can only tell you that it occurred as I described.

I understand your skepticism.

[eclipxe]

Are you sure auto steer was engaged? I also had a Tesla for a couple of years and AP absolutely slows down in curves consistently.

[kuschku]

It gets worse, if your Tesla is following a car in front of you, and they switch lanes, but you can’t switch lanes because another car is coming from behind in that lane, the Autopilot will switch nonetheless.

This almost killed a tester from the German federal motor vehicle approval agency. Their overall report is devastating, and shows the Tesla autopilot is little more than a glorified cruise control, marketed in a very deceptive way.

[cr0sh]

I'm not sure what to say when the code I recently turned in (and passed) for the path planning project of term 3 in Udacity's Self-Driving Car Engineer works better at changing lanes than Tesla's system:

https://github.com/andrew-ayers/udacity-sdc/blob/master/Term...

Then again, it does have a failure mode where occasionally, for some reason, it will direct the car to change lanes into the path of a much faster moving vehicle in the lane being changed to. Most of this is because it only runs the behavior planner every second or so in the simulation, and probably does get everything perfectly correct in the prediction part (I honestly am not sure where the problem lies, though).

[kuschku]

The problem Tesla has is that their system only has ~ 40 meters visibility to back or front.

That means if you're on the Autobahn, at say 130km/h in the right lane, and a Porsche is coming from behind at 300km/h, the Tesla will not be able to see it, and consider the lane free.

[boznz]

Remind me never to drive on a German Autobahn.

[kuschku]

It’s quite interesting, because obviously an entirely different class of issues becomes apparent when the speed between two lanes on a highway can differ by a factor of 4.

This is what you get when the speed limit actually is "unlimited".

[eclipxe]

This is not true at all. Tesla's do not use the car in front to switch lanes.

[kuschku]

It depends on what mode you set it to, but under some circumstances, it does.

[pilif]

What would these circumstances be? I have never seen my car do this.

[kuschku]

When the Tesla can not reliably detect lanes (for example, due to too dense traffic), it starts to just follow whatever vehicle is in front, and determines the lane from that vehicles movement.

This can lead to major issues, as mentioned.

[eclipxe]

No, it does not use the car in front of you to switch lanes.

[rconti]

Sounds like the issue was the steering input, not the speed. I call BS on there being a single non-construction stretch of I-90 you can't take at 70mph in a Model S. Hell, the true speed is probably much closer to 110.

Normally I'd call the issue "the driver", but since the car was automated, it was an input failure, not a curve that couldn't be negotiated at that speed.

[johansch]

Elon's goal is to get humanity to another planet. The Tesla thing is just a way to get money to do that. I thought this stuff was commonly known?

I do agree with his goal. And maybe its worth some percentage of Tesla buyer's lives? Let's not talk too much about this, okay?

[rohit2412]

I think you are being sarcastic, and people don't get it.

[johansch]

Actually not.

[mlindner]

You're getting a lot of naysayers here who take one experience and extrapolate it to mean everyone. There are a lot of Tesla drivers out there who use it every day to and from work. I suggest you try using and evaluating the system yourself.

[ghostbrainalpha]

Would you still be concerned in a situation where you were the only car on the road?

[tdees40]

Yes, there are lots of complaints about it handling curves poorly, misreading overpasses as solid objects, etc. etc.