Speed-limit recognition

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Tue 17 Jun 2025 09:37
Speed-limit recognition - Andrew-T

With some recent models able to control their speed according to local limits, two points occur to me:

- is the driver instantly able to override the control to escape a potential 'incident' ?

- for a car which recognises roadside signs, would a driver have a legal defence if prosecuted for speeding when local authorities had failed to keep the signs legible ?

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Tue 17 Jun 2025 09:56
Speed-limit recognition - mcb100
- Yes. Just press the appropriate pedal, as usual.

- No. They’re driver aids. The organic content behind the wheel is still in control of the vehicle.
That said, I don’t know whether an obscured speed limit sign would be considered a robust defence when driving a car with no speed limit recognition technology.
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Tue 17 Jun 2025 13:00
Speed-limit recognition - Terry W

More critically - modern cars collect huge amounts of data - actual speed, location, speed limit, distance from car in front, camera etc.

At present most of this data is presented to the driver in real time. However I suspect only small changes to software could create a database of all this information which could then be used as a "black box" to identify fault etc in the event of an accident.

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Tue 17 Jun 2025 14:15
Speed-limit recognition - Orb>>.

More critically - modern cars collect huge amounts of data - actual speed, location, speed limit, distance from car in front, camera etc.

At present most of this data is presented to the driver in real time. However I suspect only small changes to software could create a database of all this information which could then be used as a "black box" to identify fault etc in the event of an accident.

A few years ago a jaguar crashed at high speed. When the ECU and gearbox computer was examined it showed the speed at over 140 mph.

I'm sure lots of other cars do it too.

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Tue 17 Jun 2025 14:33
Speed-limit recognition - Andrew-T
... I don’t know whether an obscured speed limit sign would be considered a robust defence when driving a car with no speed limit recognition technology.

I suppose the basic point may be that while most drivers would continue to recognise and interpret a speed-limit sign, built-in tech might not ? Fact remains that many such signs on the route I regularly drive are slowly turning greener and even vanishing into foliage.

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Tue 17 Jun 2025 15:57
Speed-limit recognition - skidpan

The 2024 Yaris has Road Sign Assist, it simply flashes the speed limit based on the road signs it sees, not totally fool proof but a useful aid all the same.

The 2025 Corolla goes further than that. The car reads the speed signs and displays them on the dash just like the Yaris but every time the limit changes you get a bong, not an issue with that. But if you stray over the limit the bonging continues and drives you mad. Not an issue in town but on the open road and motorways it drives you mad mainly because the speedo overreads, a true 70 mph is 74 on the speedo.

Found out how to stop it bonging all the time, its 16 presses of various buttons on the steering wheel and then the car is exactly the same as the Yaris, needs doing every start though.

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Tue 17 Jun 2025 16:33
Speed-limit recognition - Lee Power

I've seen mention over on the Toyota forum on these 2025 MY vehicles of a soft touch button to silence the bonging appearing on the infotainment screen - IIRC it shows but its not functional yet & is awaiting a software update to be pushed out from Toyota to enable it.

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Wed 18 Jun 2025 09:10
Speed-limit recognition - Big John

The 2025 Corolla goes further than that. The car reads the speed signs and displays them on the dash just like the Yaris but every time the limit changes you get a bong, not an issue with that. But if you stray over the limit the bonging continues and drives you mad. Not an issue in town but on the open road and motorways it drives you mad mainly because the speedo overreads, a true 70 mph is 74 on the speedo.

Has the 2025 Corolla gone a bit further with the speed "bongs"? On my 2024 Swace(Corolla in drag) you get a little "bip" as the speed limit changes - useful. If you are over the speed limit you are subjected to three slightly louder "bongs" but it shuts up after that. However as you said speedo overreads don't help.

To be honest I've got used to the speed gubbins and my driving style has adapted to the technology - no bad thing overall. I've also changed the Adaptive Cruise settings to match the prevailing speed limit with one button press - also useful.

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Wed 18 Jun 2025 09:19
Speed-limit recognition - paul 1963

The 2025 Corolla goes further than that. The car reads the speed signs and displays them on the dash just like the Yaris but every time the limit changes you get a bong, not an issue with that. But if you stray over the limit the bonging continues and drives you mad. Not an issue in town but on the open road and motorways it drives you mad mainly because the speedo overreads, a true 70 mph is 74 on the speedo.

Has the 2025 Corolla gone a bit further with the speed "bongs"? On my 2024 Swace(Corolla in drag) you get a little "bip" as the speed limit changes - useful. If you are over the speed limit you are subjected to three slightly louder "bongs" but it shuts up after that. However as you said speedo overreads don't help.

To be honest I've got used to the speed gubbins and my driving style has adapted to the technology - no bad thing overall. I've also changed the Adaptive Cruise settings to match the prevailing speed limit with one button press - also useful.

My Swift is the same, a little annoying at first but I'm used to it now. Incidentally as far as I'm aware it doesn't actually read the signs but uses the satnav.

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Wed 18 Jun 2025 09:32
Speed-limit recognition - Brit_in_Germany

We have a Mercedes and a Renault. Generally, the Mercedes is better at speed recognition - it notices the yellow signs indicating an end of speed restriction in towns and signs on motorway gantries. It cannot understand temporary speed restrictions though (e.g. night time) and sometimes gets confused. The Renault seems to have a more basic system but apart from the yellow signs not being recognised, is generally reliable.

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Wed 18 Jun 2025 12:46
Speed-limit recognition - Big John

My Swift is the same, a little annoying at first but I'm used to it now. Incidentally as far as I'm aware it doesn't actually read the signs but uses the satnav.

As far as I can tell my Swace uses gps combined with the camera technology. It sets the speed limit as you approach a large local ongoing roadworks where signs don't exist anymore (clearly gps) and then corrects it when you drive past a 30mph limit sign for the roadworks. It also spots the roadworks sign and pops up an icon on the dash to warn of that as well. It saved my bacon re a speed van where it bipped re speed limit as I went past an obscured speed limit change sign.

Edited by Big John on 18/06/2025 at 12:47

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Wed 18 Jun 2025 16:17
Speed-limit recognition - skidpan

As far as I can tell my Swace uses gps combined with the camera technology.

Our Corolla has RSA (Road Sign Assist) which seems to suggest it depends on road signs rather than Sat Nav. So far its been 100% when you pass a speed limit change with a sign shown, it alerts you with a nice little bong. Same when there are road works signs which pop up an icon next to the speed limit. One thing I have noticed on motorways, when there are queue warnings on the matrix signs that also shows the road works alert icon.

Will have to try and spot if the speed limit display ever changes without a sign and also how quick the system reacts to changes to the speed limit (new 20mph area for example).

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Wed 18 Jun 2025 18:42
Speed-limit recognition - Terry W

It would be fairly straightforward to set up a real world test - see how many are missed along a the same route (mix of roads, 20m +) at the same time of day by a driver and automated sensor.

Assuming the human to be better even with technology at current levels may be a step too far.

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Wed 18 Jun 2025 19:15
Speed-limit recognition - Orb>>.

Well. Personally I use the Mk 1 eyeball and so far it works. There is the backup of google maps...

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Wed 18 Jun 2025 20:09
Speed-limit recognition - Brit_in_Germany

Good that you have no points on your licence. I guess the reminders are of most benefit to those who fail to take notice of the signs, where the 'bong' can mean that they keep their licence.

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Tue 17 Jun 2025 16:47
Speed-limit recognition - mcb100
This is where Renault have applied a stroke of genius with their Safety Shield button.
You set the bings and bongs and interventions you don’t want to bing, bong and intervene, and press Save.
Each time you get in the car you double tap a physical button (just to the right of the steering wheel, usually) and it reverts back to your personal settings. No need to switch off each feature individually.

Edited by mcb100 on 17/06/2025 at 16:59

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