Dangerous situation with new TACC in snowy conditions

[Andyw2100]

Also for those who wish they could have standard CC in some circumstances, just remember that TACC is CC, and you can set it to any speed you want. It will drive at that speed constantly and the only exception will be that it will slow down if something is in the way, at which point you would have turned off CC. You can turn off TACC at the same point if you want. Likewise, you wouldn't turn on CC until you were up to speed and unimpeded, so if you do the same with TACC, you get CC. Another minor difference is that if you are zooming toward a car with standard CC, don't want to slow down, but want to make a sudden lane change at the last moment, you'd have to put your foot on the accelerator to do the same with TACC. But it also means that you'd end up illegally close if you are at the point that TACC would have slowed you down.

One issue with TACC as it relates to regular CC is that if the radar is in any way obstructed it won't allow you turn on TACC. Since at this point TACC is the only CC we have, there is no "regular CC." So if TACC isn't working (or if we don't want to go against Tesla's recommendation of when not to use it), we have no way to simply set a speed and maintain it.

 

[NoMoGas]

Also this is a pretty big difference from your traditional cruise control. The fact that now we don't have the ability to just set and maintain a speed in any sort of inclement weather is a bit of a negative. With traditional cruise control there's really no downside to using it, at an appropriately low speed, in bad weather. I see why, if visibility is an issue, we wouldn't want to use TACC in inclement weather, but somehow there should still be a way to set and hold a desired speed.

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I responded to the other message first, as apparently I shouldn't have been using TACC at all, and failed to realize that. But it my own defense, I also wasn't using it as if it was 75 degrees and sunny. I was kind of using it more as an experiment, to see what it would do, and was ready to brake if need be pretty much at all times. I would not have allowed the TACC to get me into a situation where it would be braking harder than I would have braked if I had braked earlier. For all I know, it is possible that if I had waited longer, TACC may have recognized the other car and then braked quite hard, but since I was already closer than I wanted to be, and closer than I should have been for the TACC to acquire the other car as a target, I decided to play it safe and just brake.

This wasn't close to an accident or anything. I just wanted to point out to Tesla the fact that the TACC never acquired the target, and never gave any indication that it wasn't functioning.

when it's not lit blue but gray it is acting as a regular cruise control. That is the very thing you are complaining about is that it act like a regular cruise control and didn't slow down, and yet that's exactly what it did.

 

[Andyw2100]

when it's not lit blue but gray it is acting as a regular cruise control. That is the very thing you are complaining about is that it act like a regular cruise control and didn't slow down, and yet that's exactly what it did.

Do you have any idea what you are talking about?

First of all, I was not complaining. I was sharing my experience with others, which is what we do here. More to the point of your apparent lack of comprehension with respect to the Tesla TACC, I had the TACC engaged. The fact that that the small car in the display was gray does not indicate that the TACC should have been acting like a "regular" cruise control and "not slow down" as you say. What that gray car indicates is that the TACC does not currently have a target car. Since I was approaching the slightly slower moving car in the lane in front of me, I expected the TACC to pick up that car as a target car and turn blue, and then slow down. It failed to do that. Perhaps this was due to the weather. I already acknowledged that I missed the warning in the release notes about not using the TACC in snowy weather. But I've also said that I still think Tesla needs to do something about that, because if the TACC engages, it should function, and if it can't function properly in the snow, then it should not engage, because I can assure you there are plenty of people who won't have made any effort to read the release notes.

 

[bonnie]

Andy, I think everyone appreciates both you sharing your experience and your openness at acknowledging you missed the disclaimers in the release notes. (And yes, few people read manuals - and even fewer read release notes. )

I'm sure Tesla is taking all this as input to improve TACC even further. One term I threw out with my validation teams was 'human error'. We had 'use error', which didn't assign blame, but rather acknowledged that the use scenario was not ideal and resulted in a failure. And that's what I'd categorize your scenario as - easy to miss the release notes, expected a slightly diff behavior, and now you're sharing it so no one else experiences the same.

 

[EarlyAdopter]

Unless all four wheels are slipping at exactly the same speed and slipping starts at exatly same time, cruise notices that wheel is slipping and disables itself. This has happened many times for me. Not in Tesla, but in other cars.

I'm sorry, but that's just terrible advice to suggest it's ok to use even traditional cruise control in those conditions.

There are enough unexpected situations on slippery road surfaces that cruise control is poorly suited to handle, like gusts of wind or hydroplaning, that can induce the system to accelerate at the worst possible time. So much so that you'll find hat most (or all) manufacturers recommend not using cruise control on snow or in heavy rain in their instruction manuals.

From my wife's 2014 Volvo XC60 instruction manual:

And my old 2010 Audi S4:

And 2013 BMW X3:

 

[Matias]

I'm sorry, but that's just terrible advice to suggest it's ok to use even traditional cruise control in those conditions.

There are enough unexpected situations on slippery road surfaces that cruise control is poorly suited to handle, like gusts of wind or hydroplaning, that can induce the system to accelerate at the worst possible time. So much so that you'll find hat most (or all) manufacturers recommend not using cruise control on snow or in heavy rain in their instruction manuals.

From my wife's 2014 Volvo XC60 instruction manual:
View attachment 70502

And my old 2010 Audi S4:
View attachment 70503

And 2013 BMW X3:
View attachment 70504

I'm not recommending anyone to use traditional cruise in bad weather. I'm just saying, that cruise will notice wheel slipping and disable itself. So it won't increase speed, if wheel starts slipping. For instance I've experienced hydroplaning several times when cruise has been on and it has always caused cruise to immediately disable itself, because hydroplaning does not start at exactly the same time in all four wheels and causes tire rotation speeds to differ from each other

 

[Andyw2100]

Andy, I think everyone appreciates both you sharing your experience and your openness at acknowledging you missed the disclaimers in the release notes. (And yes, few people read manuals - and even fewer read release notes. ).

Thanks, Bonnie! I appreciate your taking the time to comment, and the support!

 

[CHG-ON]

May have been said but...Personally I think the system should be smart enough to disable cruise in inclement weather. It certainly has the cameras to see if it is rainy or snowy roads. My very first thought when I read the first post was that the brakes hit way too hard for snow under TACC. I wouldn't risk it.

 

[scottm]

..driving aids are aids. Not replacement for driving. Wait until auto-driving car for that... then just *trust* your TACC to be perfect. ya, right..