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Aquaplaning with Autosteer enabled

So this happened for the first time to me (in a year of owning one) the other week and thought I’d share what happens given we’re now into the winter for anyone who hasn’t yet had it happen to them;

I was cruising down the A1 at about 7pm on autosteer around 30 min south of Grantham Supercharger - was only doing around 50-60 because of the traffic - it had been pouring most of the journey down from Scotland but hadn’t had any issues…

Passing a lorry, the car veered sharply to the right (at a concrete barrier), autosteer and TACC alarmed and disconnected (no clue if a message was displayed - I wasn’t looking at the screen) and the car suddenly braked (combination of TACC disconnecting and the huge puddle that was invisible in the dark that I was now apparently in) - immediately pressed accelerator so the guy behind didn’t run into back of me but when I instinctively tried to turn away from the concrete the car was fighting me and kept trying to turn back into it… admittedly it took me a second or two to realise it wasn’t freaking out because of the lorry and was aquaplaning so that didn’t help my stress levels.

End result being all was fine (apart from my heart rate) but it seems that while autopilot freaked out and instantly disconnected another safety system had kicked in and was dealing with the problem as as soon as I stopped fighting it the car dealt with it itself.

Lesson learned from me - if using autosteer at night in heavy rain maybe consider if it’s wise and if autopilot disconnects suddenly in heavy rain don’t just assume it’s freaked out by a lorry.
 
I've also had an aquaplane moment, the car as yours just turned off TACC and Steer and then I treated it as the usual, avoid steering and pedals until grip came back. At least being the LR the AWD helped get grip earlier. That was on a back road so I didn't have other cars/trucks to worry about thankfully!
 
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GeorgeSymonds

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Mar 16, 2018
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My cousin is a motorway/highway patrol guy and he says it's not uncommon for cars to spin out if using any form of cruise control (not a Tesla specific issue) and they hit water. I think the cars first instrinct is to add more power as the water causes the car to slow down and it's the last thing you really want in the situation.
 
I barely trust autosteer when its dark let alone when its raining hard never mind the two together. I appreciate that in Scotland one or the other, if not both applies about 90% of the time at this time of year but I would not be using it in those conditions.
Yes - a little bit of complacency had certainly set in, given that it had been fine for the previous 5 hours in similar conditions - although on hindsight probably wasn’t best idea to use it on unlit stretch with what I now know is ridiculously poor drainage (which it seems the majority of motorways in south of England seem to be)! Needless to say it was off for the rest of the journey to folkstone - which took 2 hours longer than normal as the weather only got worse!

Just curious @Alistairuk What tyres and mileage/tread depth?
Standard supplied tyres with the SR+, it’s done 7000 miles so not a lot - tread haven’t measured but nothing notable wrong with them - they still look pretty new.
 
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My cousin is a motorway/highway patrol guy and he says it's not uncommon for cars to spin out if using any form of cruise control (not a Tesla specific issue) and they hit water. I think the cars first instrinct is to add more power as the water causes the car to slow down and it's the last thing you really want in the situation.
I do wonder what affect regen has on this - obviously in a normal car you take your foot off accelerator and nothing unusual happens - do it with regen and I think you actually risk making it worse (given experience of trying to stop at lights in the snow) - I think you kinda need to find the sweet spot where your pressing just enough to prevent regen kicking in but not enough to cause power to be applied. Wonder if eventually we’ll see the car smart enough to realise the skid / aquaplane and not allow regen to kick in.
 
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Billbrown1982

TM3 LR 2021 | Red | FSD
Dec 21, 2020
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I do wonder what affect regen has on this - obviously in a normal car you take your foot off accelerator and nothing unusual happens - do it with regen and I think you actually risk making it worse (given experience of trying to stop at lights in the snow) - I think you kinda need to find the sweet spot where your pressing just enough to prevent regen kicking in but not enough to cause power to be applied. Wonder if eventually we’ll see the car smart enough to realise the skid / aquaplane and not allow regen to kick in.
I was actually wondering exactly the same thing, as my instinct would be to take my foot off the gas and hold the steering wheel firm, but if that essentially puts the brakes on....

Not sure I want to be the one that tests it though!
 
Stability control systems will have immediate priority over Autopilot because they sense yaw, not road position.

I've not tried it but I would expect regen to be inhibited while the stability control is actively managing the situation.

There are a couple of places on the M1 where lane 3 and 4 flood and I've also hit standing water in the dark and needed replacement underwear afterward.

If I were in your shoes - or tyres - I'd be having a close look at the tread depth on the back tyres, even though 7000 miles doesn't sound a lot.
 
Nobody likes a smartarse, and this is not a comment towards the OP rather just a general observation… but does nobody read the owner’s manual these days? It is littered with warnings about use of any of the automatic functionality in such weather conditions.
In no way am I claiming it's an issue with the car/fault with the car - more an FYI for anyone else that may find themselves in a similar situation to not try and fight the car for control - wait until the car does its thing before you try and steer...

The car did what I would have expected it to do in the situation - disconnected autopilot threw control back to the driver (even if then another system took over fighting the driver)...

Although it would have been a lot less stressful if there was an obvious indication that whatever low-level safety system (whether it be ABS / ESP / whatever) had activated and might have saved my initial confusion over why the car was fighting me and trying to steer off the road (something that you would normally notice immediately in a vehicle with the warnings lights directly in front of you - I presume something was probably displayed on the screen).
 

M3noob

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Aug 22, 2019
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Nobody likes a smartarse, and this is not a comment towards the OP rather just a general observation… but does nobody read the owner’s manual these days? It is littered with warnings about use of any of the automatic functionality in such weather conditions.
Indeed RTFM is universally ignored.

My experience in heavy weather is that the car will take itself out of Autopilot/FSD in conditions where I wonder just how risk adverse the algorithm is! Oh, well, I'm sitting there and might as well steer and brake as required...or even take a break 😉
Polish_20211020_122647468.png
 
Tesla need to put plows in front of tires :)
When anti-lock braking system (ABS) register aquaplaning they descent and plow water away.

Regards from Sweden
 

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