Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Be Careful with Automatic Lane Changes

This site may earn commission on affiliate links.
The most recent 8.1 firmware update was a big improvement for my 2016 P100D. Autosteer is more stable and the increase from 35 mph to 80 mph on major highways actually makes it useful. I took a 220 mile trip last weekend and used it most of the way. I used the automatic lane change feature several times and it worked perfectly with one exception. After a lane change at high speed, the car abruptly slowed down for no apparent reason. The car in back of me had to brake to avoid an accident. I had my hands on the steering wheel and took over driving quickly, but it was close.
 
  • Helpful
Reactions: tiggerlily
I'm not sure if this has anything to do with automatic lane changes.

The fact is that AP2 has had some rather serious issues with slowly down for nothingness.

Now AP1/HW1 isn't immune to this, and I've had a few issues where TACC on my HW1 car has slowed down for nothing. It's also happened at least once while passing someone. In that case it could have been that I pushed the accelerator to pass them overriding the TACC, and then the TACC slowed down more quickly than I anticipated. Thereby surprising me, and pissing off the person I passed. Although I took over so fast that maybe all they really saw was the brake light briefly.

In any cases lane changes are one area you really need to be careful of the car suddenly slowing down. Due to human nature to hit the accelerator, and that sometimes it takes AP a moment or two to figure out there isn't anyone in front.
 
I also had a slowdown for no reason recently (AP1). I was on the freeway, it was raining (relevant?) and the car slowed down very quickly for no reason. I hit the accelerator to get back up to speed before being rear-ended. No more AP for the rest of that drive.
 
Seen the same — in most cases for me I think been when I've been switching from either outside lane (1) on a 3-lane interstate to the middle lane (2) and the computer picked up a car in the next lane (3) as being in my path. Or it saw a bridge and freaked. :rolleyes:
 
  • Like
Reactions: ucmndd
I find that AP2 changes lanes nicely if I am moving into a lane where a vehicle is passing by faster. However, if the vehicles are moving at about the same speed and are close, there can be a surprise slow down. Overall, I am pleased with the 17.14.35 build on two recent drives. Freeway turns are improved with only an occasional overage where tires tap the lane buttons. If vehicles are adjacent, the accuracy is improved. Nighttime Autopilot steering works very well with bright lane reflectors. I really appreciate the flashing glow around the driver display as an extra attention getter if I forget to hold the steering wheel. The constant slight steering wheel movements with AP2 makes it easier for the software to recognize that I am holding the wheel, since I tend to apply a slight bit of pressure to "help" the car steer.
 
  • Informative
Reactions: EinSV
I think there may have been some hubris in thinking they could so easily do what mobileeye did, and better, so quickly. But they'll get there. Long term it'll be an asset for the company and customers. Short term, annoying for customers who paid $5k for an unfinished product.

Or $150,000 for a car without basic safety features.
 
I've also had the mysterious sudden slow down for no apparent reason. I informed (complained) Tesla about this and they responded in a few days wanting to know the exact time and location and conditions. A few days later they called back and said the speed limit based on GPS location was incorrect. Therefore, it was not strictly a real-time AP fault as much of a data input (or data merge/cleanse) fault. That said, AP should take into consideration that if everyone else in the immediate vicinity is going 70, then for safety perhaps you should not suddenly slow to 45.
 
I've also had the mysterious sudden slow down for no apparent reason. I informed (complained) Tesla about this and they responded in a few days wanting to know the exact time and location and conditions. A few days later they called back and said the speed limit based on GPS location was incorrect. Therefore, it was not strictly a real-time AP fault as much of a data input (or data merge/cleanse) fault. That said, AP should take into consideration that if everyone else in the immediate vicinity is going 70, then for safety perhaps you should not suddenly slow to 45.
If the driver immediately takes control to undo an action of the autopilot, is that action flagged and sent to tesla for review, or placed into the cloud for cloud learning analysis? Anyone know how exactly the autopilot "learns"?
 
  • Like
Reactions: cybergates
Definitely seem to slow down issue on cruise control especially with bridges overpasses. auto lane change doesn't leave enough of a gap between u and the car behind i found when changing lanes. Overall sounds like this current version is much improved for AP2 was before but much work is still needed. It still likes to wobble in lane too much on autosteer but def usable.
 
Whenever you have an unexplained slow down using TACC or AP, such as overhead bridge, sign or gantry you could press the mic button and report the incident direct to Tesla ie say something like "Report - 405 Northbound - 14h30 - TACC - overhead gantry" - you'll see a "Thanks" notification on the driver screen.

I usually do this and noticed that 4 overhead gantries ceased to be a problem within a week of my reporting it! :)

If we all do this we'll all be helping one another!
 
I've also had the mysterious sudden slow down for no apparent reason. I informed (complained) Tesla about this and they responded in a few days wanting to know the exact time and location and conditions. A few days later they called back and said the speed limit based on GPS location was incorrect. Therefore, it was not strictly a real-time AP fault as much of a data input (or data merge/cleanse) fault. That said, AP should take into consideration that if everyone else in the immediate vicinity is going 70, then for safety perhaps you should not suddenly slow to 45.

That reply sounds strange to me. Any momentary slowdowns at highway speeds I've had have been just that, momentary. This under TACC as well as AP control. Suggesting "the speed limit based on GPS location was incorrect" would imply the speed limit in their database changes every few feet. Kind of hard to believe.

Unless the slowdown you mention was not momentary?
 
Whenever you have an unexplained slow down using TACC or AP, such as overhead bridge, sign or gantry you could press the mic button and report the incident direct to Tesla ie say something like "Report - 405 Northbound - 14h30 - TACC - overhead gantry" - you'll see a "Thanks" notification on the driver screen.

I usually do this and noticed that 4 overhead gantries ceased to be a problem within a week of my reporting it! :)

If we all do this we'll all be helping one another!
Awesome I had no idea you could do that
 
That reply sounds strange to me. Any momentary slowdowns at highway speeds I've had have been just that, momentary. This under TACC as well as AP control. Suggesting "the speed limit based on GPS location was incorrect" would imply the speed limit in their database changes every few feet. Kind of hard to believe.

Unless the slowdown you mention was not momentary?

I read other posts here which suggest that TACC/AP 'false alarms' are whiteboarded when they are reported. Before using the mic 'report' facility I used to email these to my SC where the tech people apparently much appreciated it! Run a search on 'whiteboard' and see if you can find the thread(s).
 
Whenever you have an unexplained slow down using TACC or AP, such as overhead bridge, sign or gantry you could press the mic button and report the incident direct to Tesla ie say something like "Report - 405 Northbound - 14h30 - TACC - overhead gantry" - you'll see a "Thanks" notification on the driver screen.

I usually do this and noticed that 4 overhead gantries ceased to be a problem within a week of my reporting it! :)

If we all do this we'll all be helping one another!
I was going to mention this functionality also; much better than a verbal or emailed report, because it includes enough information along with it for Tesla to fix the issue. You don't even need to include a timestamp, I believe. It knows when and where you made the report, and can geolocate what you talking about with such a description.
 
  • Informative
Reactions: Tomnook