Has anyone else encountered this behavior? I am in the right lane of two lane highway with autopilot engaged, and car slows down as if it is on the exit ramp, but I am still on the highway. I have no intention of taking the exit and it happens going past most exits. Very dangerous behavior. I'm on 16.3.2, but noticed this behavior in prior version as well. I'm not sure if this is hardware or software issue. Any guidance appreciated (and apologies if this has been covered elsewhere).
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Autopilot Dangerously Slows Down on Highway When Passing An Exit
- Thread starter Silo1231
- Start date
I notice that behavior when a car in front is exiting, and my car has latched it for some reason. Doesn’t seem to matter if the other car is completely off the freeway and fully on the exit ramp, it will still show as highlighted on my display, and my car slows like it is in the lane.
A lot of my phantom braking seems to be these type events, where the car has latched to an adjacent lane car and won’t pass it, or slows down to its speed. Seems a little worse in the latest firmware (2019.20.1)
A lot of my phantom braking seems to be these type events, where the car has latched to an adjacent lane car and won’t pass it, or slows down to its speed. Seems a little worse in the latest firmware (2019.20.1)
Thanks, yeah this is well beyond the garden variety phantom braking that I deal with when going under bridges, etc. Instead this is each and every exit the car thinks it is on the exit and the car decelerates , but the car is on the highway. I've had the car for a year and a half, and just noticed this behavior in last month or so.
Thanks, I generally put up with a bunch of autopilot fails, but this new character trait makes autopilot feature unusable and unsafe. Fingers crossed this gets fixed in future update.
Agreed. I rarely use autopilot after playing around with it for the first few weeks of ownership. I think Tesla is investing way too heavily in it and betting on it being good for FSD way too early.
This isn't an autopilot problem. It is a TACC problem. I NEVER use autopilot, and now I can't use cruise control either. I can be driving on the freeway at 70 mph with a car on the entrance ramp ahead of me going 45 mph and my car will brake hard to stay behind the merging car, even though I would have been way ahead of the other car by the time it entered my lane. The cars following me are not expecting me to hit the brakes. Very unsafe.
I've noticed this issue as well, the cars in back of me are not pleased, but the driver who is merging into the highway must be thinking, "Wow, that Tesla driver sure is courteous to slow down so agressively to let me in ... "
Part of the cause could be out-of-date on board maps.
Yesterday drove on two multi-lane divided highways that had recent construction. One is now finished after widening - and the other is in the middle of widening. Because of the widening, some of the exit/entrance ramps were moved and portions of the highway now sit where the ramps or frontage road used to be.
Especially when driving the outermost lane, I'll see phantom braking. Sometimes the TACC speed will be automatically be reduced - and other times, TACC will intentionally slow down without adjusting the set speed.
There are enough instances of phantom braking that Tesla should be able to implement improvements.
Though if the software is relying on the onboard maps for anything, that's almost guaranteed to be wrong in areas of recent road changes/construction. Tesla should shift away from updating the entire map database infrequently and instead frequently send incremental updates for the areas around where each vehicle is located - so that the area in which the vehicle will be operating will be as up-to-date as possible.
Yesterday drove on two multi-lane divided highways that had recent construction. One is now finished after widening - and the other is in the middle of widening. Because of the widening, some of the exit/entrance ramps were moved and portions of the highway now sit where the ramps or frontage road used to be.
Especially when driving the outermost lane, I'll see phantom braking. Sometimes the TACC speed will be automatically be reduced - and other times, TACC will intentionally slow down without adjusting the set speed.
There are enough instances of phantom braking that Tesla should be able to implement improvements.
Though if the software is relying on the onboard maps for anything, that's almost guaranteed to be wrong in areas of recent road changes/construction. Tesla should shift away from updating the entire map database infrequently and instead frequently send incremental updates for the areas around where each vehicle is located - so that the area in which the vehicle will be operating will be as up-to-date as possible.
Right lane prior to exit. Other cars present is not a condition to this behaviour for me. 7 or 8 exits along a major freeway consecutive had this. 3-5 mph reduction in speed then resumption of speed after passing exit ramps. Did not occur when I took the same freeway in another lane the same day. Weather was clear and sunny. Excellent lane markings. No other adjacent roads or freeways for map data to potentially grab upon.
I have seen other mentions of this in other threads under fleet speed or conditional which this seems very different....really didn't pay attention to it till it started to annoy me. One or two times, one might attribute it to other things.
This makes one drive in the left lane or constantly slow down on the right lane on a two lane divided highway. Almost like the car is saying I really need to be ready just in case they take this exit.....Oh never mind they want to keep going. Repeat. Which is strange if you have Nav on Autopilot the car should know you don't plan on taking that exit. Also happens without Nav on AP in case anyone is wondering as well.
Maps are updated and car firmware has been updated recently.
I have seen other mentions of this in other threads under fleet speed or conditional which this seems very different....really didn't pay attention to it till it started to annoy me. One or two times, one might attribute it to other things.
This makes one drive in the left lane or constantly slow down on the right lane on a two lane divided highway. Almost like the car is saying I really need to be ready just in case they take this exit.....Oh never mind they want to keep going. Repeat. Which is strange if you have Nav on Autopilot the car should know you don't plan on taking that exit. Also happens without Nav on AP in case anyone is wondering as well.
Maps are updated and car firmware has been updated recently.
Yup, this is what happens to me, except the speed reduction is much more drastic, as if the car thinks it is on the exit ramp. I was on a two lane highway in the right lane, I had the autopilot set to 60 mph, and the car spooled down to 25 mph by the exit, I made sure no cars were behind me as I let it spool down.
Wonder if the type of ramp plays a part on the speed reduction. Mine were pretty decent length deceleration ramps. Where I could see clover leafs and other types being more abrupt.
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