Mercedes A-Class Forum banner

1 - 20 of 36 Posts

·
Registered
Joined
·
693 Posts
Discussion Starter #1
There have been various posts on Speed Limit Assist with some saying how well it works whilst others like me see all sorts of errors. Having spent far too much time trying to get to the bottom of this I think I can now give some insight into why there might be so much confusion even within Mercedes.

Firstly there seem to be two distinct Speed Limit systems, Speed Limit Assist that is fitted to all models and forms a key part of the NCAP Safety Assist criteria as well as the Traffic Sign Assist feature that comes as part of the Advanced Navigation Package.

For those who have the Traffic Sign Assist feature there is no reason to read further as with this feature Speed Limit Assist seems to work pretty well. As it says in its specification it integrates camera and SatNav data to show the correct speed symbol on the dash board.

For those of us who only have Speed Limit Assist (SLA) and thought that this meant that there would always be the 'correct' speed symbol on the dash it seems we were wrong but whether this was a deliberate move by MB or not remains to be seen.

Many of us who just have SLA have experienced all manor of errors, no speed symbol before a speed sign is past, no speed symbol after a de-restriction sign, speed symbols disappearing at a roundabout or junction, spurious speed symbols appearing for no reason, 70mph not appearing on motorways for a few miles, 70mph popping up when driving over or under a motorway as well as correct and incorrect speed symbols just appearing or disappearing full stop.

The errors we are getting can seem to be random and unless you analyse them quite difficult to describe in a way that dealerships can investigate them, because of this MB have developed all manor of explanations as to why we are seeing these errors. Personally I have been given many explanations by Mercedes Technical and Customer Services which include:

The system is camera based only which is why you will not see a speed symbol before a speed sign has been past

The speed symbol disappears at roundabouts because the system doesn't know which exit you have taken

The system does not know what category of road you are on after a de-restriction sign


I have had many other explanations but the broad theme is that for SLA MB believe that they have implemented a camera only system which has lead to what most of us would see as deficiencies but MB see as 'limitations of the technology'. Be that as it may this explanation cannot be the whole story since on many occasions I have found that a wrong speed limit will pop up for no apparent reason and these instances can often be repeated at the same point in the road where there is no speed or other road sign, I have also found that these error points seem to change with each map update so in my view there is something more to this but currently I only have theories as to what this might be.

The end result though is that MB are taking the stance that the feature they call SLA suffers from limitations of the current technology and because of this it is functioning as expected ............. except that is that this morning I came across this statement in the NCAP Assessment Protocol - Safety Assist version 8.0.4 November 2018 section 4 Assessment of Speed Assistance Systems states the following:

4.4.1.2 The speed limit information must be shown or accessible at any time with a simple operation and needs to be shown at the start of the next journey (excluding the initialization period).

As you can see this totally contradicts what MB have been telling me as it clear that NCAP expect there to be a speed symbol on the dash at all times, just like you have with the Traffic Sign Assist feature :rolleyes:
 

·
Registered
Joined
·
693 Posts
Discussion Starter #2 (Edited)
I have been wondering for some time why MB bothered to develop the basic, supposedly camera only, SLA when they have a fully functioning Speed Assist function in Traffic Sign Assist.

Then I read the NCAP spec for Speed Assist features, it says that if a speed assist system uses Satnav data this data must be updated at least quarterly for 6 years which would of course cost MB in licence fees.

So it seems they have put in a cheap, but not very cheerful, very basic SLA in the base specification just to get their 5* rating.
 

·
Registered
Joined
·
78 Posts
It's annoying that my old Hyundai got it's speed limit data from the sat nav data and was so much more reliable. it was on screen the entire time and didn't rely on cameras for it to function.
 

·
Registered
Joined
·
78 Posts
As it needs to be for the NCAP 5* but MB don't seem to know this 🙄
Just like mercedes claiming dashcams are illegal in the UK and that's why they won't activate it as an option (what my dealship told me)
Love my car, but hate the fact it does some simple things very poorly, like the speed limits.
 

·
Registered
Joined
·
61 Posts
It is sad/funny to put waze on the mobile bext to the nav of the car and see the different incorrect speeds the car is giving me in Belgium... 50 when it is 30, 70 when it is 100 etcc
 

·
Registered
Joined
·
693 Posts
Discussion Starter #7
It is sad/funny to put waze on the mobile bext to the nav of the car and see the different incorrect speeds the car is giving me in Belgium... 50 when it is 30, 70 when it is 100 etcc
That sounds like an excellent idea for a new video, I already have a stock pile of videos that show many of the errors I am seeing but using Waze wold be conclusive.
 

·
Registered
Joined
·
693 Posts
Discussion Starter #8
Having hit a brick wall on this I have escalated the matter to Gary Savage the UK CEO, predictably this was picked up by the staff in the office who seem essentially to be another tier of CS, any how their first response was just to reiterate that the system is not 100% reliable due to the current technology but in the end I persuaded them to look at a video I have made of an hours drive in and around my home town. I edited this video so that it just shows the 20 instances where SLA shows the wrong speed icon which reduced the video to around 15 minutes. So in essence I gave them a video of a one hour drive where SLA could be seen to be giving the wrong speed icon for 25% of the time and on average showing an error every 3 minutes. I had hoped that I would have least have had a reply that tried to give an explanation for some if not all of the instances but instead I received this:

Thank you for bearing with me. I’ve spoken with our Technical Support team, and specifically to my colleague who specialises in the telematics side of things.

I have to apologise for my earlier email, because I incorrectly mentioned that the car relies on the map data when it hasn’t seen a sign with the speed on it for some time – this is only correct with cars fitted with Traffic Sign Assist, and not Speed Limit Assist, which your car is fitted with.

On your car, the system relies on the speed limit signs, and repeater signs, to display the speed limit in any particular area. If it hasn’t seen a sign for a while, or it hasn’t seen one at all, the system uses artificial intelligence to determine what kind of road you’re driving on.

The car determines the type of road by using the front camera, and depending on what it ‘sees’, it’ll display the national speed limit for that kind of road. For example, it’ll look out for things like lampposts and yellow lines to establish a 30mph zone, but I agree that this way of determining the speed isn’t 100% reliable when there are so many variations at play.

I understand that this might not be the answer you were hoping for, but I hope that it offers an explanation as to why you’re experiencing some anomalies when it comes to the speeds displayed.

Kind Regards,


This reply seems to me to say that either their Telematics specialist couldn't be bothered to look at the videos I sent them and just put this down to another whinging customer who unreasonably expects SLA to work correctly all of the time or MB know full well that SLA is not functioning correctly but, as they only fitted it to get past the NCAP testing which has now been completed, have no intention of giving the matter any more development time. My personal view is that they are fuly aware of the limitations of SLA but seem to have forgetten that this is a key part of the NCAP testing, not for long though as I will make sure they are made very aware of this.
 

·
Registered
Joined
·
54 Posts
...

I have to apologise for my earlier email, because I incorrectly mentioned that the car relies on the map data when it hasn’t seen a sign with the speed on it for some time – this is only correct with cars fitted with Traffic Sign Assist, and not Speed Limit Assist, which your car is fitted with.

On your car, the system relies on the speed limit signs, and repeater signs, to display the speed limit in any particular area. If it hasn’t seen a sign for a while, or it hasn’t seen one at all, the system uses artificial intelligence to determine what kind of road you’re driving on.

The car determines the type of road by using the front camera, and depending on what it ‘sees’, it’ll display the national speed limit for that kind of road. For example, it’ll look out for things like lampposts and yellow lines to establish a 30mph zone, but I agree that this way of determining the speed isn’t 100% reliable when there are so many variations at play.


...
That has to be the most confusing answer ever. The way the first sentence is constructed ('this is only correct with cars fitted with Traffic Sign Assist, and not Speed Limit Assist, which your car is fitted with.'), I can't even tell which assists they are saying you have. If I'm reading it right, I think they are saying you have SLA but not TSA. So, according to the brochure, TSA uses the camera to scan for traffic signs, which I assume would include speed limit signs. Then they are saying your car, with SLA (but not TSA), 'relies on the speed limit signs' to determine the speed limit. How is it doing that if it isn't scanning for traffic signs?

Then they are saying if a car with TSA doesn't see a sign, it uses map data, but if the car only has SLA, it tries to guess the road type by using the camera. But why doesn't a car with only SLA also use map data?

So confused now.
 

·
Registered
Joined
·
693 Posts
Discussion Starter #10
That has to be the most confusing answer ever. The way the first sentence is constructed ('this is only correct with cars fitted with Traffic Sign Assist, and not Speed Limit Assist, which your car is fitted with.'), I can't even tell which assists they are saying you have. If I'm reading it right, I think they are saying you have SLA but not TSA. So, according to the brochure, TSA uses the camera to scan for traffic signs, which I assume would include speed limit signs. Then they are saying your car, with SLA (but not TSA), 'relies on the speed limit signs' to determine the speed limit. How is it doing that if it isn't scanning for traffic signs?

Then they are saying if a car with TSA doesn't see a sign, it uses map data, but if the car only has SLA, it tries to guess the road type by using the camera. But why doesn't a car with only SLA also use map data?

So confused now.
Yup it is so confusing it even confused MB people 😂

Reading between the lines 🙄 to pass the NCAP Speed Assist tests a car has to permanantly show the current speed limit as a symbol on the dash. If map data is used to achieve this the map data must be updated at least quarterly for 6 years. To avoid the licencing costs of doing this MB have developed a camera & AI solution which they call SLA & this is fitted to all models. The only problem is that SLA only seems to have worked correctly whilst being tested by NCAP 😱

MB then seem to have integrated SLA with map data plus a database of other traffic signs that they call TSA and sell it as a premium feature, however, many people may have though to be superfluous when choosing the spec of their cars believing that SLA actually worked 😂
 

·
Registered
Joined
·
54 Posts
Thanks, that helps. So, what I think you are saying is: SLA uses road signs and AI to figure out the speed limit. But if it can't determine it, and if you have TSA, it then goes to map data, which could be out of date. And, possibly, TSA might be using a database of other road signs (other than speed limit signs), that SLA isn't, to help in determining speed (for example, a school sign or road work sign might be of use if it were taking that into account). Phew.
 

·
Registered
Joined
·
693 Posts
Discussion Starter #12
Pretty much, although with TSA I expect that it uses the map data and supercedes that when it sees a speed sign, that way it should always show you the current speed rather than out of date map data speeds.

In truth I suspect they actually developed TSA & then striped parts of it out to give a cheap cut down version that just satisfied the NCAP requirement. The trouble is I think that in the process they have lost the fundamental functionality they were looking for. Quite how they managed to pass the NCAP test though is a mystery.
 

·
Super Moderator
Joined
·
2,125 Posts
What I don’t understand, is why there are not more people (on this forum, or a Facebook group for example) complaining that their SLA isn’t working correctly?
 

·
Registered
Joined
·
54 Posts
So do we know which manufacturers are updating maps for six years? I have had cars here and in the U.S. and not one of them over the years has been accurate, to the point that I now only ever believe it if I see it do its little flashing thing that lets me know it just saw the sign. And even then, there's no saying if it missed another sign a minute later.
 

·
Registered
Joined
·
693 Posts
Discussion Starter #15
I don't use Facebook so can't comment there but here there a number who have & do complain as can be seen if you search here or look at A question for those who DO NOT have the Advanced...

One problem I found for quite some time is that some people have problems and some don't but I think most of this is to do with TSA as those with it have no problems.

Speaking to my dealer they tell me many people do complain but they can't replicate the problem, also it has taken me ages to understand what is going on and most people don't have the time or energy to keep trying to get it fixed.

Perhaps I'm wrong though, maybe it's just me and a handful of others who have the problem, if this is the case I do wonder why MB are so reluctant to look into it and why they have such ready explanations
 

·
Registered
Joined
·
78 Posts
What I don’t understand, is why there are not more people (on this forum, or a Facebook group for example) complaining that their SLA isn’t working correctly?
I only just got my car. only just realised how terrible this system is (I have SLA) compared to my previous car that only used maps (that always displayed the speed limit on the nav screen unlike this rubbish)
I did a 20 minute journey yesterday and I would say 15 minutes of that i had no speed limit displayed on my car as most of it was unsigned roads. defeats the point of the "match the speed limit" feature on my cruise control (not ACC) as the car never know what the **** speed is! I have advanced nav as I have a 2020 AMG line premium.
 

·
Super Moderator
Joined
·
2,125 Posts
I only just got my car. only just realised how terrible this system is (I have SLA) compared to my previous car that only used maps (that always displayed the speed limit on the nav screen unlike this rubbish)
I did a 20 minute journey yesterday and I would say 15 minutes of that i had no speed limit displayed on my car as most of it was unsigned roads. defeats the point of the "match the speed limit" feature on my cruise control (not ACC) as the car never know what the **** speed is! I have advanced nav as I have a 2020 AMG line premium.
That’s sounds like it’s behaving like it’s supposed to.

Map based speed limits, overridden by camera recognition = TSA.

What you have (I think) is SLA - where if there is no roadside speed sign, it won’t display anything, as it doesn’t use the map database, just the camera recognition.

There’s a couple of posts on mbclub saying how SLA has picked up the 50 on the rear of a lorry mistakenly. And another saying how clever the SLA is because it knows to ignore the signs that are only meant for HGV’s! So as far as they are concerned, SLA for them works perfectly!
 

·
Registered
Joined
·
78 Posts
That’s sounds like it’s behaving like it’s supposed to.

Map based speed limits, overridden by camera recognition = TSA.

What you have (I think) is SLA - where if there is no roadside speed sign, it won’t display anything, as it doesn’t use the map database, just the camera recognition.

There’s a couple of posts on mbclub saying how SLA has picked up the 50 on the rear of a lorry mistakenly. And another saying how clever the SLA is because it knows to ignore the signs that are only meant for HGV’s! So as far as they are concerned, SLA for them works perfectly!
Yeah, which is terrible... not saying it's working incorrectly. i'm saying it's a terrible system.
Especially when satnav based systems can display the correct speed all the time, and even cars that cost half of what I paid for mine can have this.
My car also thinks that all national speed signs mean 70 as well... that's one thing that's clearly not right,
 
1 - 20 of 36 Posts
Top