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TACC random slowing down
- Thread starter connectjunkie
- Start date
spooksman
Member
When using TACC (in the absence of a proper speed limiter!) we're seeing a place on a 30mph road where the car slows down to 20mph for 100 yards or so, then speeds back up to 30mph. It does this on both our cars (one 2020, one 2023) every time. This happens near a junction on the left, but there are no signs anywhere to confuse the system, and no other cars on the road. It also doesn't slow down going in the opposite direction on the same road.
Both cars actually do the same thing on a road near my wife's office where there is no left turn, but it does it consistently on both cars - I have tried to work out the logic, but I'm not sure there is any.
Both cars actually do the same thing on a road near my wife's office where there is no left turn, but it does it consistently on both cars - I have tried to work out the logic, but I'm not sure there is any.
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Pink Duck
Active Member
Similar thing myself but in a 40 mph zone heading ENE shortly before a left-sided junction (30 mph) not on the planned linear route.
Cnixon
Member
Sorry but I am confused here. I have experienced this more recently and my blame went straight to mapping. If the car is slowing for no visual reason then why should vision be blamed? I have long suspected, as this problem has been there since ~2020 for me - which pre dated sign recognition, that OSM is, well, too OPEN. anyone could alter the data. To make matters worse Local Councils do not clean cut trees or put signs in correct place (locally we have signs about 1m from ground) size font etc. so the car has to revert to the mapping. Personally I would like the car to have more reaction when I pass a reduced speed limit sign and TACC does nothing although it has clearly changed the speed sign symbol. I might start raising the quick bug report on these. Can we still press and hold the 'Service' button?
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Pink Duck
Active Member
Tesla does not use OSM in UK, only shoddy TomTom map data. OSM users like myself are hot on vandalism and newbie change mistakes and know it is likely more up-to-date than any other source.
OSM seems more accurate than Tesla.. Tesla had the speeds for the airport link road wrong for at least a year.
There's a road near here that the car is convinced has a traffic light on it, despite there being nothing similar nor has there ever been (it wouldn't make sense) so if you try to use AP you get a red line and 'stopping for traffic control' just randomly.
Then there's the routing that tries to go 200 yards down a farm track rather than staying on a perfectly servicable straight road..
I'm not sure what the source is, even tomtom isn't that bad. It wouldn't surprise me if Tesla were trying to do it in house.
There's a road near here that the car is convinced has a traffic light on it, despite there being nothing similar nor has there ever been (it wouldn't make sense) so if you try to use AP you get a red line and 'stopping for traffic control' just randomly.
Then there's the routing that tries to go 200 yards down a farm track rather than staying on a perfectly servicable straight road..
I'm not sure what the source is, even tomtom isn't that bad. It wouldn't surprise me if Tesla were trying to do it in house.
Cnixon
Member
Sorry I thought tesla did use OSM - cheap data etc. I agree though OSM is good for a huge amount of data but its the 'newbie change mistakes' that got me thinking the way I did. Most of these sessions of the car slowing are short lived so they are quickly being corrected. The posts above 2 cars doing the same and over multiple days does support its a mapping issue.
Pagemakers
Active Member
Pink Duck
Active Member
It doesn’t appear to be mapping as I’ve sat and watched AP speed limit readout remain constant during these slow-down events.
Cnixon
Member
Can someone explain to me and Pink why the speed on the display are 'sometimes' not related to the cars actions.
spooksman
Member
Not if it what you are asking, but when our cars do the ‘slow down’ I described earlier, the speed limit display remains showing 30mph, the car just slows for a while. It ‘feels’ like the cars know traffic slows at that point usually, and reacts accordingly, but I know that isn’t what is happening.
You know when the car slows for a bend, then speeds up again? Like that, except there is no bend!
Pagemakers
Active Member
I’m getting the same issues (not using Autosteer) in a new MYRWD (2023.44.30.8).
Since it’s mostly Brits and Aussies raising this, is this a RHD problem?
I effectively brake checked someone today when the car decided to slow from 50kph to 40kph and I wasn’t ready for it. It messed me around 6 times in the space of 3km. Because I use the “current speed” setting not “speed limit” settings, I just expected it to just stay at my set speed.
Btw, TACC remained active and the MAX speed didn’t change, the car just slowed down.
The only thing I could see that would cause it, was a few shadows on the road from a few trees.
I note too that the automatic windscreen wipers aren’t automatic unless the screen is dry.
This is the first car to actually scare me with its behaviour and I’ve owned 15 over the last 45yrs.
I’ve only had the car for two weeks, but If this is how it’s going to be, I’ll be selling soon. This kind of tech has to be reliable.
Since it’s mostly Brits and Aussies raising this, is this a RHD problem?
I effectively brake checked someone today when the car decided to slow from 50kph to 40kph and I wasn’t ready for it. It messed me around 6 times in the space of 3km. Because I use the “current speed” setting not “speed limit” settings, I just expected it to just stay at my set speed.
Btw, TACC remained active and the MAX speed didn’t change, the car just slowed down.
The only thing I could see that would cause it, was a few shadows on the road from a few trees.
I note too that the automatic windscreen wipers aren’t automatic unless the screen is dry.
This is the first car to actually scare me with its behaviour and I’ve owned 15 over the last 45yrs.
I’ve only had the car for two weeks, but If this is how it’s going to be, I’ll be selling soon. This kind of tech has to be reliable.
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Pagemakers
Active Member
Respectfully, I have no intention of "getting used to" an unpredictable (read dangerous) car.
I've started talking to the federal transport folk over here. Work has started on legislating an ADR/MVS for cruise control systems.
The challenge will be getting politicians to make it retrospective.
A bit off-topic, but I found that the steering isn't self-centering (I've checked the wheel alignment - it's fine). It takes work to keep the car in a straight line above 80kph. It seems that could also be software related although I'm already on the version that was supposed to fix "nothchy" steering.
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