Sudden slowing on AP at highway speed

[Tony17MXred22”]

I was driving south on i5 in Washington state two weeks ago going 70-75mph on autopilot with navigation on and suddenly the brakes locked up and the car was coming to a sudden stop. I hit the brakes my self and then the accelerator as quick as I could. I looked in my rear view mirror and luckily there was nobody following me. Wow that was close. So I told the guys at my service center in Portland Oregon about what happened and he said “ya we have heard that happens at times”. I asked him if I had been rear ended would Tesla stand behind the accident? He said no that the autopilot with navigation is beta status. He said I would have to give him the exact location on i5 and he would pass it onto engineering and they would have to go in and change the programming in the system to tell the cars not to jam the brakes at that location. That did not sound very reassuring to me.

I also notified Tesla corp from my Tesla account and they responded with a boiler plate statement that was not very satisfying. I love my car and its the best automobile I have ever had. I was counting the other day and I have owned more than 50 cars so far and this is the best. However If I were to be killed in an accident because of some programming error that would be tragic. I love the autopilot and have driven 14,000 miles in ten months using a lot of autopilot. This is the second time the car did this brake locking up situation. The first time it was just for a split second and then then car recovered and accelerated on its own.

So I think I know why the car is doing this. I would like to advise others to be aware of this situation. I believe the car thinks its running into a wall when this braking accrues. What I believe is happening is when I am driving on a downhill interstate with an overpass in the middle of the hill the car sees the dark background of the hillside and when the overpass comes into play is when the car gets close to the overpass and the car thinks because its a solid straight line on the horizon / overpass it thinks there is a wall in front of the car and slams the brakes on.

Has anybody else had this happen?

Thank you
Tony

 

[wgood33]

Whew that is an intense story. I have driven my Model 3 only 1800 miles so far. I have noticed the autopilot gets confused when I am driving in a single lane highway that converts into a two lane highway. It cannot decide which lane to choose. Autopilot is for freeways I think but your story proves we have a long way to go in the tech.

 

[alloverx]

So Tesla has a WhiteList of where not to brake?
Sounds risky, what if you actually have someone cut you off right there. Hopefully the code is well tested

 

[bob_p]

The AP software when operating under NOAP, AutoSteer or just TACC is subject to "phantom braking" due to incorrectly identifying an object ahead requiring the vehicle to slow or incorrect/missing/obsolete data in the onboard speed limit database.

Both of these issues should be correctable over time, as Tesla continues to improve object recognition with the AP sensors and finds some way to get more accurate data on the current roads & speed limits.

AutoSteer has improved considerably over the past year for AP 2.x - and I expect we'll continue to see improvements with the above issues.

 

[terrywhite]

Usually happens to me when an overpass casts a shadow on the road ahead of me. Autopilot thinks it’s an object and starts breaking.

 

[Rockster]

Phantom braking is a known occurrence. As Bob said, above, it should get better over time.

 

[kavyboy]

A quick search on just this forum turned up a report of this almost 2 years ago. I'm pretty sure I remember hearing about it before that, however. So, I guess it's been "getting better" for a while.

 

[sorka]

I was driving south on i5 in Washington state two weeks ago going 70-75mph on autopilot with navigation on and suddenly the brakes locked up and the car was coming to a sudden stop. I hit the brakes my self and then the accelerator as quick as I could. I looked in my rear view mirror and luckily there was nobody following me. Wow that was close. So I told the guys at my service center in Portland Oregon about what happened and he said “ya we have heard that happens at times”. I asked him if I had been rear ended would Tesla stand behind the accident? He said no that the autopilot with navigation is beta status. He said I would have to give him the exact location on i5 and he would pass it onto engineering and they would have to go in and change the programming in the system to tell the cars not to jam the brakes at that location. That did not sound very reassuring to me.

I also notified Tesla corp from my Tesla account and they responded with a boiler plate statement that was not very satisfying. I love my car and its the best automobile I have ever had. I was counting the other day and I have owned more than 50 cars so far and this is the best. However If I were to be killed in an accident because of some programming error that would be tragic. I love the autopilot and have driven 14,000 miles in ten months using a lot of autopilot. This is the second time the car did this brake locking up situation. The first time it was just for a split second and then then car recovered and accelerated on its own.

So I think I know why the car is doing this. I would like to advise others to be aware of this situation. I believe the car thinks its running into a wall when this braking accrues. What I believe is happening is when I am driving on a downhill interstate with an overpass in the middle of the hill the car sees the dark background of the hillside and when the overpass comes into play is when the car gets close to the overpass and the car thinks because its a solid straight line on the horizon / overpass it thinks there is a wall in front of the car and slams the brakes on.

Has anybody else had this happen?

Thank you
Tony

If you didn't get the collision warning beep prior to the braking event then it didn't brake because it thought it was going to hit something.

 

[eye.surgeon]

Might want to edit your post to indicate you had a phantom or inappropriate hard brake on AP. The brakes didn't lock up, that has a specific meaning which is not possible with ABS systems. If you didn't leave 4 black stripes of rubber down the freeway, your brakes didn't lock up.

 

[ChrML]

I hit the brakes my self and then the accelerator as quick as I could.

Not sure why you decided to hit the brakes too. When they look at the data, they probably think the car was right since you confirmed it by braking too

Phantom braking happens from time to time. Just hit the accelerator to quickly override it.

You or Tesla won't get the blame if you get rear-ended. The guy behind will for driving too close and also not paying attention.

 

[Tony17MXred22”]

Terry White you stated “this happens”. Wow how ofter does this happen? Just one time scared the s_th out of me. I guess the first time is the worst.

I am sorry the brakes did not lock up. The ABS operated at full force.

The reason I pressed the brake down was to disengage the system. Like kicking off cruise control. I wanted to shut the sysem off and let me take over. It was a split second reaction. I just wanted out of the situation i was in. We dont receive instructions from Tesla that informs us how to circumvent a computer glitch.

I posted this same thread on the “Tesla Forum” and i was suprised to see there is a long thread already there called “Dangerous Autopilot”. You guys may want to check this out.

I am not here to create problems for Tesla I just want people to know this my happen to them and to be allert. I wish Tesla would tell us what causes the braking and how we can all work together to correct the situation.

Autopilot is getting better... we just need to work out the problems without people getting in accidents. There is no acceptable reason why a car should activate ABS inappropriately.

Thanks
Tony

 

[ecarfan]

I was driving south on i5 in Washington state two weeks ago going 70-75mph on autopilot with navigation on and suddenly the brakes locked up and the car was coming to a sudden stop.

I doubt the car would have come to a stop; What people describe as “phantom braking” is something that some people have experienced with EAP and it can occur in any model Tesla. There are multiple threads about it on TMC. I’ve had it happen in my X multiple times; the car slows down suddenly by maybe 5mph and then either resumes or I press the accelerator pedal to override it.

I’m sure it is startling to some people. In my experience it occurs much less than it used to a year or so ago.

EAP is not perfect. We all need to pay close attention while using it.

 

[lundse50]

When I first got my X in late 2016, I had this problem when using autopilot especially where the overhead signs were large, just south of DC for example on 95. As the previous message states, it has gotten better. I no longer have this issue south of DC.

 

[ewoodrick]

Usually happens to me when an overpass casts a shadow on the road ahead of me. Autopilot thinks it’s an object and starts breaking.

I'm pretty sure that the hypothesis that it's a shadow is wrong. I've had the same issue at night. I think that it is just mis-identifying the bridge.

 

[ewoodrick]

I was driving south on i5 in Washington state two weeks ago going 70-75mph on autopilot with navigation on and suddenly the brakes locked up and the car was coming to a sudden stop. I hit the brakes my self and then the accelerator as quick as I could.

Has anybody else had this happen?

Thank you
Tony

Is it possible that you may be exaggerating a little? The brakes should never lock up, even if you try.
Maybe they were heavily applied? This happens, just add accelerator.

 

[wgood33]

[QUOTE="Tony17MXred22”,There is no acceptable reason why a car should activate ABS inappropriately.[/QUOTE]
I am a new Tesla owner and am on a free 30-day trial of the Autopilot. The engineer in me would accept the "beta testing period" required to refine AP. I did not purchase AP because $5000 is more than double what I think it should be. I was expecting this car to have adaptive cruise control, not having this is my biggest disappointment with this car. I expected it. Any $50k+ car has adaptive cruise, is Tesla strong arming me into an extra $5k by excluding this feature?

 

[Tony17MXred22”]

Don’t get me wrong I love my MX... I just wanted to let other know of this situation.

I use my autopilot all the time while I am on the interstate. It works great most 98% of the time. I know when its not proper to use the AP. It works great with good painted lines and while traveling in the center lane. You can not beat it. Takes lots of stress out of driving... Its the 1-2% that is a little unsettling. So hopefully it will get better with other drivers uploading AP data to the mothership (Tesla programmers). I can say in just 11 months of ownership my MX on AP is much better then it was 11 months ago.

This was just a very scary moment for me and I wanted to share it. I would say the AP is worth the $5,000. Because it will get better as time goes on. It looks like the only thing we are missing on our cars is a “Lidar” I guess this is much better then the radar we are equipped with.

 

[365gtb4]

Usually happens to me when an overpass casts a shadow on the road ahead of me. Autopilot thinks it’s an object and starts breaking.

Yes, this also happens on I-10 underpass in Banning CA.

 

[bob_p]

The jury is still out on lidar vs radar & cameras.

Humans don't have lidar or radar, and only use 2 video sensors, that can rotate about 180 degrees - and are able to operate vehicles safely.

Lidar makes it easier to determine the location of objects around the vehicle. The front facing radar, coupled with the front facing cameras should be able to do that for objects in front of the vehicle. For the sides and rear, Tesla has assumed they can use the images to identify objects and their size, relative location, and relative speed. While that would be easier with lidar, it's possible (but not yet proven) Tesla can do it only with video cameras, plus the limited range proximity sensors.

The other aspect of this - humans also interpret what the objects are doing - a nearby vehicle using turn signals or emergency flashers - or a first responder with the flashing lights or directing traffic with hand signals or something that might jump in front of the vehicle without warning (such as an animal, child, biker, …). For Full Self Driving to be successful , the software will also likely need to take those input into account - and lidar isn't a solution for that - while Tesla's strategy of interpreting the camera data may prove to more successful.

Will be interesting to see how this plays out over the next few years... Tesla has a lot more test data to use than the other manufacturers, which may help them address these challenges faster.

 

[terrywhite]

I'm pretty sure that the hypothesis that it's a shadow is wrong. I've had the same issue at night. I think that it is just mis-identifying the bridge.

Or that there is more than one cause. I never said that it’s the only reason. However, it is one that I’ve been able to recreate in the same patch of highway.