Do Not Sell My Personal Information Jump to content


Road Sign Assist


Recommended Posts

Hi All,

How does anyone find the accuracy of Road Sign Assist (RSA)?  

Generally it seems ok, but on a "smart" motorway, I am finding that the system will pick up the numerical speed limits fine (e.g. a temporary 50mph restriction) but on exiting the section it fails to recognise the national speed limit sign and you drive for miles with a 50 limit showing.

My vehicle is a 2021 RX.

Paul

Link to comment
Share on other sites


Only used RSA for last 10days in new 2018Gs300 . It seems to show a lot of random numbers including 90 and 120 whilst on a motorway. I agree that the temporary restrictions and exit from them is particularly troublesome.

David

Link to comment
Share on other sites

Just now, Fig said:

It seems to show a lot of random numbers including 90 and 120 whilst on a motorway

Possibly picking up the speed limit signs on the rear of articulated lorries and the like?

 

Link to comment
Share on other sites

I found that the RSA on both my previous GSF and current RX is a bit of joke. 80% of the time it works OK but there are some signs it just cannot read. On my local dual carriageway it is convinced the limit is 110, (should be 50) . I don't think actiing on  a wrong RSA figure is going to cut much ice with a magistrate!  It is also affected by rain, ice or dirt on the screen. All in all a useless complication that the marketing people thought we must have. In my view if you're not sufficiently alert to pick up on changing speed limits then perhaps you shouldn't be behind the wheel.

Link to comment
Share on other sites

>Possibly picking up the speed limit signs on the rear of articulated lorries and the like?

Hmmmm could be in that case.  My RX does not seem to suffer from that particular issue, and I do remember reading about a camera software upgrade on Lexus Tech that fixes that exact issue.

David - you might want to mention this to your dealer next time you have a service.  My vehicle is a '21 so will have the latest software - and I don't have that specific issue, so perhaps the updates between 18 and 21 have fixed it.  Next time I'm logged in to Lexus Tech I'll try to find that again and post you the TSB number.

the latest software, however, still has issues, particularly coming out of a speed restriction back to national speed limit.

The irony with this is that speed limits programmed into the sat nav database (as on MM15 systems) work fine (if they are kept up to date) except for dynamic limits on smart motorways.... which is one reason why the RSA system should be an improvement.  However, this is precisely the scenario where it does not work properly (at least for me)!

Cheers,

Paul

Link to comment
Share on other sites


>In my view if you're not sufficiently alert to pick up on changing speed limits then perhaps you shouldn't be behind the wheel.

Indeed, although it's supposed to be a driver aid, so it would be better not to have it, than have it display the wrong thing.

On that note, I cannot see how to use only the database of speed limits rather than the camera (as is done on my wife's 2015 NX).  If I turn off RSA on the RX, then the speed limit notification totally disappears.

On the web pages, it sounds really impressive....

https://www.lexus.co.uk/discover-lexus/technology/lexus-safety/road-sign-assist/#road-sign-assist

Paul

Link to comment
Share on other sites

Just now, NemesisUK said:

Do any manufacturer's vehicles use RSA to set cruise control limits?

The Lexus system kind of does.  If you enter a new speed limit on cruise control, you can move the cruise control stalk up/down and it will go straight to the new limit, rather then going in the usual 5mph increments.  (I have only tried this once and it seemed to work).

I believe Bentleys can change the target speed with no driver intervention when the speed limit changes.  Not sure about other manufacturers.

Paul

  • Like 1
Link to comment
Share on other sites

2 minutes ago, PDM said:

I believe Bentleys can change the target speed with no driver intervention when the speed limit changes.  Not sure about other manufacturers.

 

That could be rather alarming, should the system misread the sign! 

Much rather the Lexus implementation, where the driver has to instigate the change

Link to comment
Share on other sites

Just now, NemesisUK said:

That could be rather alarming, should the system misread the sign! 

Much rather the Lexus implementation, where the driver has to instigate the change

especially with a Bentley W12 to pull you along!  You could be doing 120 in the time it takes you to try to cancel the cruise control!

  • Like 1
Link to comment
Share on other sites

7 minutes ago, NemesisUK said:

That could be rather alarming, should the system misread the sign! 

especially if you don't notice you've just increased your speed to 120 mph :yahoo:

tooooooo much silly technology methinks

Malc

sorry i missed the above post !

Link to comment
Share on other sites


There was a story going round that our friends in Brussels were going to get manufacturers  to prevent cars going above the speed picked up by the RSA. Methinks they need to get the technology to work first.

  • Like 1
Link to comment
Share on other sites

15 minutes ago, 08ISF said:

There was a story going round that our friends in Brussels were going to get manufacturers  to prevent cars going above the speed picked up by the RSA. Methinks they need to get the technology to work first.

https://www.evo.co.uk/news/22326/mandatory-speed-limiters-to-be-fitted-to-all-new-uk-cars-after-2022

https://www.autoexpress.co.uk/car-news/103530/uk-set-to-adopt-eu-mandated-speed-limiters

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share



×
×
  • Create New...