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Comment by akerl_ | Hacker News Reader

If enhanced cruise control in my non-Tesla routinely slammed on the breaks out of nowhere, I’d be pissed about that too.

Tesla’s marketing is optimized to convince users that the software is better than it is, and the software’s failure modes align horribly with the worst case: when things are working, everything is smooth, but without warning the car will suddenly decide to make a dangerous active change (swerving, braking, etc) in a way that can kill a driver who is even partially distracted.

Put the above together and it starts to look like Elon has created a perfect storm for traffic accidents.

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I'm not justifying how Tesla's assistance works as I've driven a rental and it really is glorified cruise control right now.

That being said, I have a Honda with assistive braking and it is terrible. Shadows, pot holes, ghosts all seem to cause it to brake and not in predictable ways which is frustrating. I only leave it on, because I imagine one day I won't quite react fast enough to someone in front of me and it will save me the pain of rear ending someone.

But I definitely almost did when it slammed the brakes on a highway off ramp and got me rightfully honked at by the car behind me.

Whats worse is I'm not even sure if mine could receive updates at any point. Maybe at the dealership.

I have a Subaru with assistive braking (EyeSight) and it does the exact same thing on a very specific off ramp. My best guess was that it's detecting the big yellow "turn" sign right before the loop. It's about big enough to be the back of a car to the primitive detection.

That's not a solution for you, just thought I would share commiseration. Your experience with it is slightly worse than mine has been but I leave mine on for the exact same reason.

IMO, Tesla is a bit worse, but I agree with this in principle. I've had other cars phantom brake in similar situations.

The worst phantom brakes that I've had from AP were cases where a car really was creeping into my lane a bit. Its just that hard braking wasn't the right fix for the situation as a slight swerve was safer.

There's no "slam" on the brakes you are being sensational.

It's a slowdown typically within the range of regeneration, not even touching the brakes, and it's nowhere close to squeaking tires or the dramatic scenario you describe

I’m not sure what you’re talking about.

I own a Tesla Model 3 as my daily driver. Phantom breaking works exactly the way I described it. And it’s not hard to understand why: the intent of the system (like all other emergency braking systems on modern cars) is to avoid a collision with a perceived object in front of the car. A gentle regenerative slowdown wouldn’t even make sense in that scenario.

Phantom breaking behaves the way a human driver would if they were attempting to stop short of an impending front collision. It just so happens that the Tesla is happy to engage that behavior in all kinds of fun scenarios, like if somebody leans an inch into your lane, or a bridge has a shadow it doesn’t like, or it decides the potholes are a force field in front of your car.

we must have different highways. I've never had anything close to full braking. only slowing for disabled vehicles/highway barriers

or maybe you're using it off highway?

I’ve experienced it on highways, but as I noted in a parallel comment, if Tesla thinks Autosteer isn’t viable on non-highways, it’s odd that they make it available. They have no trouble identifying road type and using it to determine speed restrictions for autosteer, and no problem disabling autosteer if they can’t ID the lines.

Maybe the phantom breaking is so harsh in your car it’s giving you amnesia, because it’s a well-understood Tesla failure mode on the Teslamotors subreddit, TMC, and every other Tesla owner forum I’ve seen.

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