Satnav & Speed Limits

Faults and Technical chat for the Volvo XC40
scottpcs
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Post by scottpcs »

My car has just come back from being in for a week at the dealer and one of the things I mentioned (that wasn't even looked at but that's for another thread) was the satnav's woeful reliability where speed limits are concerned.

I've come to the conclusion that the satnav either isn't reading speed limit signs or that at the very least, doesn't recognise the national speed limit sign. There are a few roads around me that have been national speed limit for as long as I've been alive yet the car stubbornly refuses to accept that and believes they are 30 mph limits. I even know one road where the car will suddenly think it's 30 mph half way along it, even though there are no signs or junctions that would cause it to think that.

The loan car I've been driving around in for the last week has been a 2018 XC90 with supposedly the exact same system in but yet it correctly indicated the speed limit around 95% of the time. It also displays the national speed limit sign in the dash when approaching which the XC40 doesn't (in fact I've never seen the national speed limit symbol in the dash yet.) By comparison, I reckon the XC40 is only correct around 60% of the time and isn't reliable enough to use.

The technician at my dealer confirmed that their demo car at least exhibits the same issue on the same roads so I've left it with him to investigate further. I've come down hard on him and said it's a safety issue as the car could be cruising along at 60 mph then suddenly drops the anchor when it believes the speed limit is half that!

How are you finding yours and have you had similar experiences?
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chingf0rd
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Post by chingf0rd »

Sorry for my ignorance but are you talking about the Traffic Sign Recognition in the dash or something in the satnav? The TSR is pretty accurate in mine - picks up 30 immediately passing one and can see the 40 if it is closely followed on. it can also spot 20 restrictions and school warning triangle. Not seen the national speed limit one.
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scottpcs
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Post by scottpcs »

chingf0rd wrote: Tue Sep 04, 2018 9:40 pm Sorry for my ignorance but are you talking about the Traffic Sign Recognition in the dash or something in the satnav? The TSR is pretty accurate in mine - picks up 30 immediately passing one and can see the 40 if it is closely followed on. it can also spot 20 restrictions and school warning triangle. Not seen the national speed limit one.
I'm talking about the speed limit that's displayed in the dash. TSR does work as you describe EXCEPT for the national speed limit (NSL) signs - the car seems to ignore these for the most part.

One particular road near me has clear NSL signs as you go into it from a 40 mph limit and yet the car displays a 30 mph limit in the dash. It even prempts this by displaying a 30 limit behind the current 40 when the NSL signs are some way off. It doesn't seem to matter whether TSR is enabled or not, the speed limit displayed in the dash is wrong on certain roads and especially where NSL roads are concerned.

The tech tried telling me that the car works exclusively from a camera at the front 'looking' for speed limit signs and not from satnav data but I think I've clearly proven him wrong today. As for the car changing the displayed speed limit on the dash half way down the road with no signs or junctions to cause it to do so, explain that?!
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kirsty_s2k
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Post by kirsty_s2k »

Defo can't be only from the camera as it shows what's coming next when it's not in view. I've not noticed issues with it getting these wrong around here - might be data specific to maps for your area. We've had issues for years that certain old software Sat Navs have our postcode linked to the same street name, but in a village three miles away . . . probably a similar data issue.
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scottpcs
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Post by scottpcs »

kirsty_s2k wrote: Wed Sep 05, 2018 12:56 pm Defo can't be only from the camera as it shows what's coming next when it's not in view. I've not noticed issues with it getting these wrong around here - might be data specific to maps for your area. We've had issues for years that certain old software Sat Navs have our postcode linked to the same street name, but in a village three miles away . . . probably a similar data issue.
You could be right but what I don't get is that the exact same mapping software is used for other cars in the Volvo range such as the XC90 I had on loan but yet that car was pretty much spot on in the same area and the same roads. Looking at the downloads page on Volvo's website, the latest maps are a single one-size-fits-all download and it lists several cars that this update is for, including all cars in the XC range.

With this in mind, I can't think what else could be different on the XC40 that would cause it to mis-read certain roads?
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Brandyman
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Post by Brandyman »

I have found mine to be fairly accurate and reliable. Definitely picks up national speed limit signs.
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scottpcs
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Post by scottpcs »

Brandyman wrote: Wed Sep 05, 2018 1:25 pm I have found mine to be fairly accurate and reliable. Definitely picks up national speed limit signs.
When you say it picks up NSL signs, does the NSL symbol appear in the dash or simply '60' or '70' ?
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kirsty_s2k
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Post by kirsty_s2k »

scottpcs wrote: Wed Sep 05, 2018 1:08 pm You could be right but what I don't get is that the exact same mapping software is used for other cars in the Volvo range such as the XC90 I had on loan but yet that car was pretty much spot on in the same area and the same roads. Looking at the downloads page on Volvo's website, the latest maps are a single one-size-fits-all download and it lists several cars that this update is for, including all cars in the XC range.

With this in mind, I can't think what else could be different on the XC40 that would cause it to mis-read certain roads?
That's a good point actually - why would different cars with the same software behave differently :(
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Brandyman
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Post by Brandyman »

scottpcs wrote: Wed Sep 05, 2018 1:27 pm
Brandyman wrote: Wed Sep 05, 2018 1:25 pm I have found mine to be fairly accurate and reliable. Definitely picks up national speed limit signs.
When you say it picks up NSL signs, does the NSL symbol appear in the dash or simply '60' or '70' ?
I think it starts as the symbol but then changes to 60 or 70.
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scottpcs
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Post by scottpcs »

Brandyman wrote: Thu Sep 06, 2018 12:47 pm
scottpcs wrote: Wed Sep 05, 2018 1:27 pm
Brandyman wrote: Wed Sep 05, 2018 1:25 pm I have found mine to be fairly accurate and reliable. Definitely picks up national speed limit signs.
When you say it picks up NSL signs, does the NSL symbol appear in the dash or simply '60' or '70' ?
I think it starts as the symbol but then changes to 60 or 70.
If you're right then that answers a critical question. The tech and I believe that the XC90 that behaved correctly and DID display the NSL symbol has an older version of the software installed and therefore we suspect the problems lie in the latest version.

The tech is going to take the XC90 out again on the same roads to verify that it works as it should and then update it to the latest software to see if he can replicate the issue. If he can then he'll have to submit a technical report to Volvo, watch this space.
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