Roadsign assist very inaccurate

[birdseye]

Roadsign assist seems very inaccurate and I was relying on this to help avoid a speeding ticket here in UK,

  today I had it show 60 whilst driving in a 40 area, several times it showed 40 when in a 30, The car is a  brand new 2 days old 2016 Prius. It can't be dirty sensors on the car as it's in pristine condition so Is this a common fault or does my car need spectacles

[BhxTrev]

Hi Vic,

I've got the same problem! My Prius Excel which I had on 2nd Sept 2016, has frequently given me false speed information. On at least one occasion & I don't know why, it can suddenly change from MPH to KPH! I thought it was me but it's obviously a problem with the Roadsign Assist. If like me you have Touch 2, this also gives the speed limit information that seems to be more reliable. Maybe they'll put this right eventually?

[ian rooke]

Hi I have had the same the sign recognition on my Business+ has read from 5 MPH to 130 MPH while the Sat Nav would be showing the correct speed limit.

[FROSTYBALLS]

Has anyone mentioned the issue to their Toyota dealer and hence Toyota?

[BhxTrev]

Hi Frosty,

Good point. I've got to take my my car in for the brake recall so will mention it. Quite astounded that Toyota recall a virtually brand new car but then again I'm so please that unlike some well known marques they do admit to problems that do arise & more importantly are ready to put the matter right. Folks out there ought to think about these important aspects when buying a new car. To me Toyota score full marks. 

[ian rooke]

Hi yes I have to my Toyota dealer and to the Toyota  Blog got nowhere,

[GreenJuice]

I reckon mine is correct about 90% of the time. Today I was driving past King's Cross in London and it showed the speed limit at 100mph! You would have thought the programmers would at least give it some intelligence about national speed limits.

[kithmo]

22 minutes ago, GreenJuice said:

I reckon mine is correct about 90% of the time. Today I was driving past King's Cross in London and it showed the speed limit at 100mph! You would have thought the programmers would at least give it some intelligence about national speed limits.

Sounds about right for London 

Seriously though, I treat the RSA as a gimmick and don't rely on it. It can only read what it sees and if it misses a speed sign or misreads a different sign as a speed sign then that's what it will show. There are so many signs in city streets now that it, like us humans, can get confused.

[birdseye]

 

3 hours ago, BhxTrev said:

Hi Vic,

I've got the same problem! My Prius Excel which I had on 2nd Sept 2016, has frequently given me false speed information. On at least one occasion & I don't know why, it can suddenly change from MPH to KPH! I thought it was me but it's obviously a problem with the Roadsign Assist. If like me you have Touch 2, this also gives the speed limit information that seems to be more reliable. Maybe they'll put this right eventually?

 

Yes, I have  touch 2 with go, only once did the satnav display the wrong speed but that would be an error in the map database due to a recent speed limit change

So glad it's not just my car then,  this is my second day with the car & apart from that all seems very good indeed

[PeteB]

4 hours ago, GreenJuice said:

I reckon mine is correct about 90% of the time. Today I was driving past King's Cross in London and it showed the speed limit at 100mph! You would have thought the programmers would at least give it some intelligence about national speed limits.

 

3 hours ago, kithmo said:

Sounds about right for London 

Seriously though, I treat the RSA as a gimmick and don't rely on it. It can only read what it sees and if it misses a speed sign or misreads a different sign as a speed sign then that's what it will show. There are so many signs in city streets now that it, like us humans, can get confused.

Yes, sounds about right to me too.

As I understand it, RSA also will display no overtaking signs, and warns you (subject to your warning settings) if it thinks you're about to disobey.  I can't confirm as I haven't seen any on my travels so far.

However, I normally drive with my TomTom for directions (about 20,000% better than the built in one).  On a long trip, I program the destination into both, partly out of interest, and partly so that if the suction mount detaches from the BeanBag base I can use the T&G2+ until I can stop safely and reattach.

I would say they are also both wrong about 10% of the time, but not always in the same places.  Sometimes all three systems display a different speed (occasionally all three wrong too!).

I came close to turning RSA off, but I like it as a reference, and whatever any of them say, I make my own decision, but use them to challenge me to double check what I think the correct limit is.

DashCam:

It's a shame, since the Gen 4 Prius has a front and rear camera, they didn't link it to a recording device (even as an extra cost option), so that it could have a built in black box.  This could even record info such as lights on/off, horn use, indicators and brake lights that would be very difficult for the add-on variety.  Given DashCams appeared over 12 years ago, I can't believe no manufacturer offers a built in option (as far as I know).

[Anthony Poli]

I reckon mine is correct about 90% of the time. Today I was driving past King's Cross in London and it showed the speed limit at 100mph! You would have thought the programmers would at least give it some intelligence about national speed limits.

 

Sounds about right for London 

Seriously though, I treat the RSA as a gimmick and don't rely on it. It can only read what it sees and if it misses a speed sign or misreads a different sign as a speed sign then that's what it will show. There are so many signs in city streets now that it, like us humans, can get confused.

Yes, sounds about right to me too.

As I understand it, RSA also will display no overtaking signs, and warns you (subject to your warning settings) if it thinks you're about to disobey.  I can't confirm as I haven't seen any on my travels so far.

However, I normally drive with my TomTom for directions (about 20,000% better than the built in one).  On a long trip, I program the destination into both, partly out of interest, and partly so that if the suction mount detaches from the BeanBag base I can use the T&G2+ until I can stop safely and reattach.

I would say they are also both wrong about 10% of the time, but not always in the same places.  Sometimes all three systems display a different speed (occasionally all three wrong too!).

I came close to turning RSA off, but I like it as a reference, and whatever any of them say, I make my own decision, but use them to challenge me to double check what I think the correct limit is.

DashCam:

It's a shame, since the Gen 4 Prius has a front and rear camera, they didn't link it to a recording device (even as an extra cost option), so that it could have a built in black box.  This could even record info such as lights on/off, horn use, indicators and brake lights that would be very difficult for the add-on variety.  Given DashCams appeared over 12 years ago, I can't believe no manufacturer offers a built in option (as far as I know).

Funny thing you should mention a black box. In the manual for the Yaris, it does say it records how the car is driven over the last 30 seconds. It also says the information is only released if ordered by police.

Sent from my iPhone using Tapatalk

[PeteB]

22 hours ago, FROSTYBALLS said:

Has anyone mentioned the issue to their Toyota dealer and hence Toyota?

Any point?

[PeteB]

1 hour ago, Anthony Poli said:

...Funny thing you should mention a black box. In the manual for the Yaris, it does say it records how the car is driven over the last 30 seconds. It also says the information is only released if ordered by police.

I think that's true of most modern cars with lots of electronic systems, but I believe the intended purpose of the data is for diagnostics and normal operation of the car (such are airbag operation, fuel management and the increasing amount of data displayed to the driver, like average speed and mpg).

[Anthony Poli]

12 minutes ago, PeteB said:

I think that's true of most modern cars with lots of electronic systems, but I believe the intended purpose of the data is for diagnostics and normal operation of the car (such are airbag operation, fuel management and the increasing amount of data displayed to the driver, like average speed and mpg).

Yes, thats the reason it says.

[thecaretaker]

Mine seemed fairly accurate during the summer months, but I'm getting misread signs a fair bit now. Then again, many speed signs are covered by trees or green algae, so can't blame the car for that. More down to the state of British roads. Does anybody ever clean road signs in the UK anymore?

 

EDIT: Thinking further on this, the road markings are in a very poor state too. I wonder if that would effect the lane assist?

[PeteB]

Mine doesn't always see signs that are very clear (as is my screen!), even in the summer, but it has got worse with the darker mornings and evenings.

It also sometime sees signs that aren't there - 110 mph seems a favourite, and various speeds with a diagonal (cancel) line through.

Other times, having misread or missed a sign, it gives me the impression the computer is overloaded with higher priority tasks (like a Windows PC often is) and for several miles it fails to respond to prominent, clear signs that it usually recognises.

According to the manual, it also displays no overtaking signs and until it is cancelled warns if it thinks you are disobeying.  I've not seen any no overtaking signs since I got the car, so can't verify.

[PeteB]

2 hours ago, thecaretaker said:

...Thinking further on this, the road markings are in a very poor state too. I wonder if that would effect the lane assist?

I've found lane assist very reliable even when I struggle to see them (even in the dark!).

On a deserted (minimal camber) road I've even tried pointing slightly towards the centre line and holding my hands a few mm away from the wheel, and it gently steers the car back on course.  Not quite Tesla Autopilot territory, but impressive!

The thing I like about these safety aids (especially AEB*), is that whilst I advocate only using them as backup, they do not get distracted, tired, use mobile phones, text while driving (or watch DVDs like the guy who died in a Tesla recently!).  That's not to say they can't be fooled, but they are pretty impressive.

[* I had resolved that I wouldn't buy my next car unless it had all three types of AEB (urban, inter-urban and pedestrian).]

Edited November 28, 2016 by PeteB
"resolved that I would buy" - oops

[thecaretaker]

3 hours ago, PeteB said:

...According to the manual, it also displays no overtaking signs and until it is cancelled warns if it thinks you are disobeying.  I've not seen any no overtaking signs since I got the car, so can't verify.

No, I've not come across an no overtaking sign either yet.

[johalareewi]

Does the camera spot those "speed limited" stickers on the back of lorries and vans?  A lot of the foreign ones have 110 stickers.

[PeteB]

1 minute ago, johalareewi said:

Does the camera spot those "speed limited" stickers on the back of lorries and vans?  A lot of the foreign ones have 110 stickers.

Good thought!   Next time it happens I'll see if there's such a vehicle nearby.

If I can I'll trigger my Dashcam and say what speed is showing, so I can review later.

[Heart my toyota]

On 25/11/2016 at 4:42 PM, birdseye said:

Roadsign assist seems very inaccurate and I was relying on this to help avoid a speeding ticket here in UK,

  today I had it show 60 whilst driving in a 40 area, several times it showed 40 when in a 30, The car is a  brand new 2 days old 2016 Prius. It can't be dirty sensors on the car as it's in pristine condition so Is this a common fault or does my car need spectacles

Same problem in my 2017 Rav4 Hybrid.  Was doing 65 displayed on the speedo on a motorway with nothing around to give a false reading, but the Roadsign assist was showing a 90 mph speed limit.  This is definitely a bug in the software, it should never show a speed higher than the national speed limit of the country, in my case the UK.  

PS  I checked under 'settings', the car is set m/g and not km/l.  I'm not aware of any other settings to check.   

Hopefully Toyota will bring out a fix . . . yesterday.  This is a known (and dangerous) bug.  What if a foreigner uses the Roadsign assist display, it is going to assist him/her into an accident or a large fine.     :-(    I hope for better from Toyota.           

[Heidfirst]

it's an aid only, you are not meant to rely on it.

"it should never show a speed higher than the national speed limit of the country, in my case the UK" & what if you leave that country & go into another with a higher limit (afaik it does not require a satnav to operate so it doesn't know where you are)?

It's a Continental AG system. No doubt it will improve as we progress from generation to generation

You will find similar complaints about the same (or similar) system in other manufacturers' cars ...

[FROSTYBALLS]

The second generation TSS will be rolled out from 2018, which uses more compact and easier to install hardware, and a different type of radar - 

 

 

[Devon Aygo]

There is a known issue which only affects Japanese/Asian built cars with TSS ( Hilux, Land cruiser, Prius, Rav4 they use a Denso system over the Continental in EU built cars ) where the speed limit displayed for the RSA switches to KMH ( settings still show MPH )

The first issue is with the recognition of certain signs with multiple colours such as the no overtaking sign. as the TSS cameras only see in black and white they rely on shades of grey and under certain circumstances ( dirty signs, light reflections etc  ) the TSS see's the wrong shade tricking the TSS into thinking it is seeing a Continental EU sign version resulting in the TSS switching to KMH

The second issue is the system does not correct itself when it does see UK signs again.

Apparently a fix has been devised which is undergoing road testing at present once it is confirmed as OK then it will be pushed to dealers to fix customers cars.

At present should it occur, restarting the car will reset the TSS/RSA

 

[16_Auris_HSD]

On 11/26/2016 at 3:47 PM, Anthony Poli said:

DashCam:

It's a shame, since the Gen 4 Prius has a front and rear camera, they didn't link it to a recording device (even as an extra cost option), so that it could have a built in black box.  This could even record info such as lights on/off, horn use, indicators and brake lights that would be very difficult for the add-on variety.  Given DashCams appeared over 12 years ago, I can't believe no manufacturer offers a built in option (as far as I know).

Funny thing you should mention a black box. In the manual for the Yaris, it does say it records how the car is driven over the last 30 seconds. It also says the information is only released if ordered by police.

Sent from my iPhone using Tapatalk

I'm glad manufacturers don't offer built in dashcams (except Citroen) since as with most these things it starts as a great idea and ends up being abused. For example the "ordered by police" bit is applicable to when police stop you, I know of instances where HGV drivers were requested to show the footage to the police when stopped and it was only to help the police "judge" the skills of the driver.