Road Sign Assist

[PDM]

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

[Fig]

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

[NemesisUK]

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?

 

[08ISF]

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.

[Fig]

Ahh yes i did wonder where from as i hadbt seen road signs telling me to go at 120

[PDM]

>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

[Fig]

Ok thanks. will have a chat to them . i need to get the keys programmed to shut the windows too

David

[PDM]

>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

[NemesisUK]

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

[PDM]

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

[NemesisUK]

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

[PDM]

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!

[Malc]

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 

tooooooo much silly technology methinks

Malc

sorry i missed the above post !

[08ISF]

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.

[NemesisUK]

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