MrBadger
Badger out
On many occasions, the speed limit is not suitable for road or conditions. Even if you know the speed limit of the road, accelerating up to it is not the smartest move.
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- Thread starter mpandrew
- Start date
On many occasions, the speed limit is not suitable for road or conditions. Even if you know the speed limit of the road, accelerating up to it is not the smartest move.
Glan gluaisne
Active Member
My experience has been that engaging TACC always causes the car to accelerate to the maximum speed limit it thinks applies, irrespective of any other speed restriction that may be in force. The car always needs some driver input to change the speed under these conditions, and 99.99% of the time this action will cause any temporary speed limit to be exceeded for a short time. With average speed cameras this may well mean getting a ticket, as just a short period of driving in excess of the limit will take the average above it, unless the speed is reduced to below the limit for long enough to cancel it out.
interbear
Active Member
MrBadger
Badger out
The speed offset is a global setting. The offset does more than control the TACC limit. It also sets the speed limit warning for example. The offset is active all the time, either as a warning when manually driving, or as the speed offset on TACC/AP. I'm not going to want to use the same offset (relative or absolute) across different scenarios. I don't see why a -20mph global offset needs to be set just to stop the car wanting to accelerate to 70mph in a 50mph zone just because its got the speed wrong or because the car thinks it knows better what speed I want to travel at than I do, I hope this all gets a rethink in time for when limitations on use of TACC are officially relaxed. You shouldn't need to use a workaround just to use a feature in many ordinary circumstances.
RTFM
Now what I don't know without trying (and I've had a drink tonight so will in the morning) is whether the word "plus" there means it ignores any negative offset, I drive with a +3 set.
So to the comment
If you are uncomfortable driving at the speed limit on TACC or AP then set a negative offset in Speed Assist,
Personally I never use these features anywhere other than on motorways, driving at the limit or +3 is no big deal. I understand that if you activated it on a narrow NSL road it would be quite startling, but I wouldn't feel comfortable with TACC there at all.
Attachments
You were replying to this quote
so your point about "accelerating to 70mph in a 50mph zone" was already covered.
Glan gluaisne
Active Member
WTF should anyone who has been driving cars with cruise control for at least 25 years, suddenly need to adopt such a bizarre and unworkable bodge as to set the global offset, before they set off each journey, to a value they think might be needed during the trip?
A typical trip for me will involve driving along a stretch of single carriageway A road, that the NSL applies to for much of the way. In practice it's not safe to drive at that speed, about 50mph is more sensible, so for that stretch the offset would need to be set to -10mph. That road then connects to a stretch of motorway, the first part of which has the normal 70mph limit, so the offset then needs to be removed. A few miles on there is a long (as in 15 mile) stretch of motorway with a 50mph average speed limit, so for that stretch the offset needs to be changed again to -20mph (as the car cannot yet detect the average speed limits that are used on some motorways).
This is just completely insane. Any normal car will just use the speed at the time that cruise is engaged as the set speed. All cars, except the Tesla Model 3, behave like this, and always have done. It's an inherently safe system, that doesn't need the driver to do anything other than engage and disengage cruise control as required. Quite why Tesla feel there is a need to make drivers take positive action every time cruise control is engaged, in order to drive at the desired set speed, isn't clear, but there is no way that this makes sense for the majority of scenarios in my regular journeys.
A typical trip for me will involve driving along a stretch of single carriageway A road, that the NSL applies to for much of the way. In practice it's not safe to drive at that speed, about 50mph is more sensible, so for that stretch the offset would need to be set to -10mph. That road then connects to a stretch of motorway, the first part of which has the normal 70mph limit, so the offset then needs to be removed. A few miles on there is a long (as in 15 mile) stretch of motorway with a 50mph average speed limit, so for that stretch the offset needs to be changed again to -20mph (as the car cannot yet detect the average speed limits that are used on some motorways).
This is just completely insane. Any normal car will just use the speed at the time that cruise is engaged as the set speed. All cars, except the Tesla Model 3, behave like this, and always have done. It's an inherently safe system, that doesn't need the driver to do anything other than engage and disengage cruise control as required. Quite why Tesla feel there is a need to make drivers take positive action every time cruise control is engaged, in order to drive at the desired set speed, isn't clear, but there is no way that this makes sense for the majority of scenarios in my regular journeys.
MrBadger
Badger out
The post was about the speed offset being a global kludge that controls other functions and should not be needed just to allow TACC to be used in a controlled way for many common scenarios.
If
... but my point is that you are changing the behaviour to add more effort into the majority case so that effort can be reduced in the minority case. You could just as easily engage TACC and keep your current pressure on the accelerator (which means the speed of the car doesn't change) - set your desired speed and then take your foot off the accelerator.
On saying that - an option that can be toggled off or on wouldn't offend me
... but my point is that you are changing the behaviour to add more effort into the majority case so that effort can be reduced in the minority case. You could just as easily engage TACC and keep your current pressure on the accelerator (which means the speed of the car doesn't change) - set your desired speed and then take your foot off the accelerator.
On saying that - an option that can be toggled off or on wouldn't offend me
Because its better ? Maybe 25 years ago you would have been saying "why should I learn how to use this new fangled cruise control - I can use a throttle "
For your typical trip why not engage TACC while keeping your foot on the accelerator (speed doesn't change while you do this) and then use the thumbwheel to set the speed to 50.
Glan gluaisne
Active Member
How on earth can doing something that is very clearly not what the driver intends be better?
If I want to cruise at 70mph then I can accelerate to 70mph and engage cruise, as normal. If I need to drive at 50mph, then I want to engage cruise at 50mph and have the car hold that speed. What I don't want the car to do is decide that I'm driving too slowly, when it clearly doesn't recognise the speed limit that applies, and start accelerating the car when I engage cruise.
Maybe a tiny percentage of owners like having the car take over control, and possibly getting them fined for speeding in the process, but I suspect the majority don't. I want the car to fail safe at all times, and fail safe in this case means none of the car systems causing the car to accelerate above the speed determinde by the driver.
Well yes, you can do this but it shouldn't be necessary so is an irritation. The past couple of days I've done a good bit of motorway driving which in recent months is something of a rarity for me. I was looking forward to seeing how TACC and Autopilot had come on as I have had several software updates since the last time I tried it in that scenario.
(Bear in mind that I frequently try Autopilot in more borderline circumstances so am very used to how it reacts and am very forgiving of its limitations because I know it is not intended to work presently on non dual carriageways.)
I have to say I was very disappointed in the motorway performance of both TACC and Autopilot. Autopilot wanted to drive past large articulated lorries with inches to spare on the left side. I would normally be driving towards the outside of my lane if there was no vehicle on my right. It would sometimes hesitate when going past a couple of lorries whilst at other times it would ignore them. If there was a vehicle ahead in my lane that was travelling more slowly it would frequently not lower my speed in a gradual way but would carry on at its set speed and then have to slow down with a noticeable deceleration before matching our speeds. I had to keep apologising to my passenger and explaining that I wasn't intentionally driving like an idiot but was allowing the car to manage the speed. As time went on I learned how to predict traffic scenarios that were going to be too challenging for the car and switched out of TACC/Autopilot to avoid the incidents of sudden deceleration. Coming back to the TACC activation speed I found that I had to work around those limitations because it initially wanted to accelerate to 70mph when activated in 50mph zones.
The result of all this is that I spent less time in TACC and Autopilot than I would have spent using simple cruise control in our Fiesta on the same journey. Fortunately I love the way the car drives and enjoy being in direct control of the car so this is less hardship than it might otherwise be!
I read reports of other owners driving for considerable distances with Autopilot engaged. I find this very surprising. Maybe if you use it more you get used to the characteristics of unnecessary slowing and accelerating and driving too close to other vehicles. I haven't noticed any significant improvement in these issues over several software updates. Maybe it's slightly more capable than last year but that might be wishful thinking.
.. but it does do what I intend it to do - drive to the speed limit. The issue isn't that, its that you have encountered situations where it could do better at detecting the speed limit - and those situations are the exceptions rather than the rule so it makes no sense to me to default to the exception. The fix isn't to stop it driving to the speed limit (and as I've said if I don't want to drive to the speed limit, I keep my foot on the throttle and adjust to the speed you want to go at)
We have different expectations
- maybe I am a tiny percentage - you prefer a dumb cruise control I actually quite like the current implementation.To me the fix is to make the speed limit recognition better (and it has come on leaps and bounds in recent months), but we're allowed to disagree. However having a neither one way or another system only adds to confusion - it should be as simple as the choice between it does everything or it does nothing but sit at the speed you set.
The issue is that nobody can make a system which performs exactly the way that each individual would like it to. (The ID.3 system works differently again and there is a whole thread on a German forum with people asking for different things.)
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Jason71
Well-Known Member
And yet it seems to be the overwhelming opinion from people that that is what they want. Its not just a numbers game anyway. Its also risk reward. The minority case as you call it is quite a big minority given the amount of road works we have and in those instances it can be dangerous to your health or licence in its current form.If
... but my point is that you are changing the behaviour to add more effort into the majority case so that effort can be reduced in the minority case. You could just as easily engage TACC and keep your current pressure on the accelerator (which means the speed of the car doesn't change) - set your desired speed and then take your foot off the accelerator.
On saying that - an option that can be toggled off or on wouldn't offend me
Given that this is not how any other systems work the majority of us are used to accelerating to the speed we want then engaging cruise. I don't find this a big hardship.
I guess we will have to hope for a toggle option then
Yep, I noticed it after the latest "upgrade" too. If the TACC was set it didn't change when AP was engaged...now it does - it's really frustrating.
There is another issue. As recognising speed limit sign improves, the ability to pick up signs from side streets may well become more of a problem. I’ve got 3 on one my trips. Each has 30 limit, and the car picks up every one. Trouble is, I’m on a 60mph road. I’d never even noticed them!
I noticed this on a road i use every day. The road i use is a 30 (but not sign posted) but the road that runs next to it is a 20 and has signage. My car reads the 20 and sits at 20. until the next sign about a mile up the road.
Glan gluaisne
Active Member
Whilst various work arounds have been suggested to reduce the potential for drivers to inadvertently exceed a speed limit when they engage TACC, all require additional driver input in order to maintain safety or comply with the law. Adjusting speed control settings on the screen every time TACC is used isn't that great a solution, IMHO, neither is quickly winding the speed down with the scroll wheel every time. My view is that the car should always, without exception, default to behaviour that is both safe and that remains within the law. It's not acceptable, IMHO, to have as the default operating state one that may cause the driver to inadvertently exceed a speed limit.
For the minority (and so far it seems only two here want the car to behave as it does at the moment) then perhaps there could be an option to have TACC default to the maximum allowable speed, plus or minus any set offset, whenever it is engaged, but I believe there is an urgent need to have a default setting option that makes TACC behave like every other car that has some form of cruise control, which is to maintain the speed at which it is engaged, unless the driver specifically requests a speed change.
For the minority (and so far it seems only two here want the car to behave as it does at the moment) then perhaps there could be an option to have TACC default to the maximum allowable speed, plus or minus any set offset, whenever it is engaged, but I believe there is an urgent need to have a default setting option that makes TACC behave like every other car that has some form of cruise control, which is to maintain the speed at which it is engaged, unless the driver specifically requests a speed change.
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