Mk 8.5 speed limit warning useless and dangerous

[Adam1986uk]

I'm finding the speed limit warning super annoying on the mk8.5. It can be temporarily deactivated but turns on again next time you start the car.

About 30% of the time it detects the wrong speed limit and so alerts you incorrectly - the technology simply isn't good enough.

The adaptive cruise control also uses the sign detection to set the speed. On a journey this weekend, it twice decided the speed limit was 100mph. It then automatically set the cruise control to 100mph on the M25, see image attached (photo taken by passenger the second time it happened, luckily I managed to brake before exceeding the speed limit).

You can see the speed limit it detected on the right in the red circle and the ACC auto set to the same in green on the left side. Crazy!

[Carlosfandango]

You can turn off the cruise control automatically adjusting to speed limits in the settings, you can also turn off the ACC being able to adjust speed due to road layout, I’ve had these both turned off since I first used the ACC and experienced the same as you, once off the cruise control is adjusted manually using the steering wheel buttons like normal.

[fredgroves]

Blimey it's still doing that on the Mk8.5?

Other than the limitations of it seeing speed signs for parallel roads, mine has been OK a few dozen software updates ago.

Initially it used to get weird things like deciding the speed limit was 85kmh (50mph) but set it to 85mph! But that was a couple of years ago.

[ar899]

Had a 24 plate T-Roc on hire recently and it was doing it. 70-30 at one time when a residential road ran parallel to the A road I was on. I got into the mindset of trying to predict when it would happen......

[ajmoir36]

Interesting to see VW have learnt nothing from the mk8.

[The_Doc]

I’ve seen this behaviour on other cars before, usually cause by European Lorrie’s with 100 km/h signs on the back indicating a speed limiter. It’s sh!t when it happens, but it’s never done it for me in my 8.

[Shooey]

I had this happen to me this week on the M4 between Reading and Heathrow whilst in an average speed check zone at 50mph. The car literally just dropped a gear and started to accelerate quite hard. The ACC had set itself to 100mph.

Quite concerned, if it had done that at a fixed camera location then I’m pretty sure that would have meant points.

Not really sure what to do, VW will no doubt say they can’t find any faults so seems a bit pointless.

I’ll try the speed limiter next time but it’s definitely something to watch when using ACC.

I'm finding the speed limit warning super annoying on the mk8.5. It can be temporarily deactivated but turns on again next time you start the car.

About 30% of the time it detects the wrong speed limit and so alerts you incorrectly - the technology simply isn't good enough.

The adaptive cruise control also uses the sign detection to set the speed. On a journey this weekend, it twice decided the speed limit was 100mph. It then automatically set the cruise control to 100mph on the M25, see image attached (photo taken by passenger the second time it happened, luckily I managed to brake before exceeding the speed limit).

You can see the speed limit it detected on the right in the red circle and the ACC auto set to the same in green on the left side. Crazy!

[fredgroves]

If you want to turn the speed limiter off permanently then get obd11 and fix it.

I did the same to the lane assist on my mk8. Same process.

[joe6]

Need yet another dash cam to record the display as evidence!    On my local section of the A1 the speed display on my 7.5  always registers 60mph. Technology definitely not up to the safety hype being promoted yet.

[baronebirra]

Hi there,

I've been noticing this same issue. Basically, the system is a bit too eager to read every sign. It picks up on junction speed limits even when you're not turning, causing unnecessary slowdowns. Like, if the main road is 70 but the exit is 40, the car will brake for the exit even if you're staying straight. That's pretty risky!

Predictive driving that slows down in case of curves or at the entrance of towns is more tolerable: in some situations it could even be useful.