Speed limiter (ISA = Intelligent Speed Assistance)

TonyLexus · June 30

I'm a little confused, and the web doesn't answer the question - do new Lexus models all now have ISA? This being the system that reads from road signs and GPS and resists (but doesn't stop) exceeding a speed limit. I have a new RX450h+ on order, built in May and due for delivery in next few weeks.

Thanks in advance

Tony

GSLV6 · June 30

Yes. Should be on all new models. I have it on my 4th gen. It basically raises alerts, with the posted speed limit showing on the HUD, which turns red if you exceed the S/l, but also triggers an annoying alarm bell, which thankfully can be toggled off in the menus. The EU are introducing mandatory limiters in all new cars which physically limit speeds using RSA cameras together with GPS, but defeatable within the menu system, so you can exceed the limits at your own risk. Personally, I think there's far too much interference in personal freedoms and whilst I'm not condoning speeding, I strongly object to the one state EU trampling personal freedoms as whatever is bound over within the EU gets bound over here too in relation to motoring and car manufacturing requirements.

TonyLexus · June 30

Thanks Paul, but therefore your car doesn't have the full-blown ISA. You say it has an audible and visible system but ISA can also physically slow the car and/or show a resistance at the pedal (I think ISA does anyway).....which you can accelerate through, at the pedal. Do all new Lexus car models now have this latter system installed??

Edited June 30 by TonyLexus
correction

Barry14UK · June 30

All new cars or those in the showroom awaiting sale have to be fully compliant. The European block wanted it and I suppose it was hard for UK to opt out of what was seen as a safety measure. I read that you can override the system but that you have to do this for every journey.

TonyLexus · June 30

Thanks Barry. There are three main types of speed limiters, each with a distinct mode of operation:

Informative or Advisory ISA: Warns the driver by displaying a symbol or alert when the speed limit is exceeded, reminding them of the legal limit.

Supportive or Warning ISA: This adds resistance to the accelerator pedal, making it harder to press down when driving over the speed limit.

Intervening or Mandatory ISA: This system automatically reduces engine power if the vehicle exceeds the speed limit, ensuring a gradual reduction in speed without using brakes. This system is akin to cruise control, maintaining the legal speed limit.

It appears, though I can't confirm this, that the law will allow single systems, or combinations, of the above.

My question is what have Lexus adopted for new cars for 7 July 2024?

Jayemef · July 5

I've just got a new Lexus this week and it has this feature. It is driving me mad that I have to keep setting this every time even just to turn the sound off but keep the visual prompt.

Linas.P · July 5

On 6/30/2024 at 1:11 PM, TonyLexus said:

Thanks Paul, but therefore your car doesn't have the full-blown ISA. You say it has an audible and visible system but ISA can also physically slow the car and/or show a resistance at the pedal (I think ISA does anyway).....which you can accelerate through, at the pedal. Do all new Lexus car models now have this latter system installed??

All cars since 2022 (January I think) have all hardware for ISA, but only cars sold since July 2024 have it configured as such that alarm automatically turns on when you start the car every time. So the cars from 2022 are identical in terms of parts, but the difference is that on cars sold before July this year, you can go into the menu and turn off the alarm... and it stays off. After July, it will automatically turn on again every time and it is obviously very annoying to go trough the menus and turn it off.

I wonder if somebody would find the ways to crack this system and update it, such that it could be turned off like in older cars.

As for what specific ISA Lexus uses, by on my experience driving current models it seems like combination of Informative/Advisory ISA and Supportive/Warning ISA. However, there isn't any resistance in pedal, it is more like "dead zone" (all Lexus for a while now have "throttle by wire", so it is just a matter of ECU accepting the accelerator or ignoring it), basically when you reach the speed limit the pedal becomes kind of numb and you need to press it past certain point (maybe over 50% travel), before it starts working again. Obviously before July it was possible to turn this off, but now you will need to do it at the start of every journey.

TonyLexus · July 6

13 hours ago, Linas.P said:

...pedal, it is more like "dead zone" (all Lexus for a while now have "throttle by wire", so it is just a matter of ECU accepting the accelerator or ignoring it), basically when you reach the speed limit the pedal becomes kind of numb and you need to press it past certain point (maybe over 50% travel), before it starts working again.

Thanks Linas.P, this was the method I was querying - I had heard that Lexus had some 'pedal system' now inbuilt. I'll find this out myself, in about 12 days time...

GMB · July 6

The answer to this 1984ism is how easy the manufacturer makes it to turn off every time. My car has stop/start that always kicks in but I can turn it off simply with one press of an easily located button. Maybe the same will apply to speed limitation?

It's a bit of a faff every time you start the car though = foot on brake - press start - press map button to get map on full screen - press stop/start to turn off that feature-Foot on brake again to select drive/reverse and .......off we go...... Maybe we should change the name to Nannylexus?

To add insult to injury in Wigan tomorrow the council are adopting a pie limiter to prevent the locals eating too many pies in one go.

GSLV6 · July 6

It's an objectionable interference by the EU but sadly one we have to live with. There'll always be the very occasional circumstance whereby during what is judged to be a safe overtake, within posted limits, the clown you're overtaking decides that he/she doesn't want to be overtaken, and will speed up. In such circumstances (with my advanced instructor's hat on) the way that is safely dealt with is to slow down and resume a safe position behind them, but what if a car intending as you are wishes to join the overtake and cuts the safety space? You have to plan for these incidences and try and manage the rear space by allowing sufficient room but there will always be an occasion where you'll end up compromised. The only safe way is not to overtake if there's any doubt or perceivable risk.

As for motorways, I see no excuse for three figure speeds. If there's lorries ahead overtaking lorries and traffic builds up, sometimes the safest option is if towards the head of such a queue, to overtake the bunch rapidly to clear the hazard. If 70 allows this, then that will be fine with ISA. For those accepting the risks, you have the ability to turn it off at that point, or accelerate past the nanny limiter at the risk of your licence and once clear, slow back to your cruising speed. Not condoning it, but just pointing out that whatever the circumstance, it's about hazard perception and planning to make smooth progress.

Many of these low carbon initiatives, such as the mandatory 60 limits on the M5 through Birmingham are a nonsense as they probably have the opposite effect, but such areas are usually where traffic is dense, so a little restraint is called for. I dread motorway driving these days (due to the appalling driving standards on show and lack of patience) but one thing that does work well are variable limits preventing sudden bunching up. Lexus have to follow the construction and use Regs for the EU and as such we just have to learn to live with the consequences and become more thinking drivers.

Motorcycles don't yet have these features but that's a matter of time. For my sins, I ride for Blood Bikes and we have no exceptions to exceed statutory limits, even on emergency runs but we are trained to make safe, smooth and rapid progress within posted limits.

GMB · July 6

23 minutes ago, GSLV6 said:

Motorcycles don't yet have these features but that's a matter of time. For my sins, I ride for Blood Bikes and we have no exceptions to exceed statutory limits, even on emergency runs but we are trained to make safe, smooth and rapid progress within posted limits.

Maybe it's just me but it is very hard to keep a modern motorcycle within any speed limit, the lower the limit the more difficult it is. If anyone doesn't understand why I will be pleased to elaborate. I doubt there will be any takers😚. Let's just leave it at 0 to 100 in under 6 seconds!

Linas.P · July 6

1 hour ago, GSLV6 said:

It's an objectionable interference by the EU but sadly one we have to live with. There'll always be the very occasional circumstance whereby during what is judged to be a safe overtake, within posted limits, the clown you're overtaking decides that he/she doesn't want to be overtaken, and will speed up. In such circumstances (with my advanced instructor's hat on) the way that is safely dealt with is to slow down and resume a safe position behind them, but what if a car intending as you are wishes to join the overtake and cuts the safety space? You have to plan for these incidences and try and manage the rear space by allowing sufficient room but there will always be an occasion where you'll end up compromised. The only safe way is not to overtake if there's any doubt or perceivable risk.

As for motorways, I see no excuse for three figure speeds. If there's lorries ahead overtaking lorries and traffic builds up, sometimes the safest option is if towards the head of such a queue, to overtake the bunch rapidly to clear the hazard. If 70 allows this, then that will be fine with ISA. For those accepting the risks, you have the ability to turn it off at that point, or accelerate past the nanny limiter at the risk of your licence and once clear, slow back to your cruising speed. Not condoning it, but just pointing out that whatever the circumstance, it's about hazard perception and planning to make smooth progress.

Many of these low carbon initiatives, such as the mandatory 60 limits on the M5 through Birmingham are a nonsense as they probably have the opposite effect, but such areas are usually where traffic is dense, so a little restraint is called for. I dread motorway driving these days (due to the appalling driving standards on show and lack of patience) but one thing that does work well are variable limits preventing sudden bunching up. Lexus have to follow the construction and use Regs for the EU and as such we just have to learn to live with the consequences and become more thinking drivers.

Motorcycles don't yet have these features but that's a matter of time. For my sins, I ride for Blood Bikes and we have no exceptions to exceed statutory limits, even on emergency runs but we are trained to make safe, smooth and rapid progress within posted limits.

UK is not part of EU, so if they wanted to they could have ignored this... But no - they absolutelly want this, this whole speeding thing is very convenient money maker and saver. Basically saying that all the accidents and all the deaths and all the issues are all about the speed is simple excuse, which is very convenient and governments around the world will play this excuse as long as they can (and they likely will be able to do it forever).

Because let's think what is alternative - fix the roads?! That costs money, nobody wants that. Make roads better, improve layout, make signage clearer - that also costs money! Actually invest money in training drivers or policing the roads to catch the real trouble makers who go double and triple speed limits, whilst also under influence and in cars that barely legal - no, too much work. Simple solution - make speed limits impossibly low and have the car to enforce them - simple, effective and makes money... yes we take that.

What is most surprising to me is that majority of people drive, it is primary mode of transportation by big margin, but people are just not willing to stand-up for their rights and freedoms when it comes to driving. Even drivers themselves put little to no effort on combating this.

2 hours ago, GMB said:

The answer to this 1984ism is how easy the manufacturer makes it to turn off every time. My car has stop/start that always kicks in but I can turn it off simply with one press of an easily located button. Maybe the same will apply to speed limitation?

It's a bit of a faff every time you start the car though = foot on brake - press start - press map button to get map on full screen - press stop/start to turn off that feature-Foot on brake again to select drive/reverse and .......off we go...... Maybe we should change the name to Nannylexus?

To add insult to injury in Wigan tomorrow the council are adopting a pie limiter to prevent the locals eating too many pies in one go.

I actually wanted to compare it with start-stop systems, because they are kind of similar in this way... they are annoying, they don't work in UK (in other countries they work better) and particularly in IS200t and RC200t they are annoying and you have to turn them off every time. Also note - if you put your car in Sport/Sport+ then it gets disabled by default.

Anyhow - NO... disabling ISA is buried in the menus and it is annoying. Sure - after doing it for 100th time it may become muscle memory, but it is not simple to turn off.

Spock66 · July 6

I don't advocate speeding but there are some circumstances where it is appropriate.

Road rage incident and you need to get away from some lunatic.
Passenger with an emergency medical condition.

Linas.P · July 6

6 minutes ago, Spock66 said:

I don't advocate speeding but there are some circumstances where it is appropriate.

Road rage incident and you need to get away from some lunatic.

Passenger with an emergency medical condition.

To be fair... neither of the are very valid reasons for speeding. I am playing devils advocate here, because I am fundamentally against speed limits overall, but getting away from lunatic you are kind of becoming one, and passenger emergency is kind of grey zone - from perspective of "safe driving activists" they would call it selfish, basically you put others at risk to deal with emergency of your own.

For that reasons I never look for excuses when speeding, I just do it.

My key problem is that speed limits are inherently arbitrary, in 90% of the cases they have no justification i.e. justification could be "known dangerous stretch of the road", but it is rarely the case. 70MPH national limit is prime example, it absolutelly absurd and outdated, made arbitrarily in 1965 as knee jerk reaction to some speed testing on public roads. As temporary measure no less! And we still have it... why?! So I would get rid of ALL speed limits and would rely on driver choosing "safe speed", but obviously drivers should be properly trained and equipped with knowledge of how to correctly judge what is safe speed... which also let's just agree 80% of the drivers are incapable of and will never be capable of. I probably would leave only very few limits in real known danger spots, which can't be reasonably be made safe e.g. residential access road, parking lot, road outside of school, but all other roads I would make by default unlimited. Perhaps advisory speed limits can be there, like the ones we have on smart motorway... they can advise close to 0C, or when it is snowing or there is heavy rain that temporary limit is 70MPH, but else go as fast as it is safe... and in modern cars in good mechanical condition, with decent tyres 100MPH, 120MPH etc. are safe speeds.

Let me shorten this - for me to respect speed limit I need justification, I do not accept blanked limits "just because", I want to see 30MPH limit and I want to see justification that it is because there is school in 100m - fair enough. But otherwise it insults my intelligence that I am forced to crawl at 30MPH because government can't trust me to know safe speed for the conditions.

So the core of the issue - if speed limits would be set fairly and based on genuine need, then it would be fine to enforce them. Now majority of the limits exist for no reason or as a means of collecting the money from motorists. And in such circumstances ISA becomes real issues and dystopian measure.

Spock66 · July 6

One speed limit I find pretty stupid living in a rural area, single track twisty road with high hedges on both sides (basically a farm track), max safe speed is around 20mph, but they put up national speed limit signs everywhere.

GSLV6 · July 6

Yes, which includes most of Wales!

@ Linus....the UK may have adopted or retained some EU rulings, and whilst I agree with your sentiments, as a car market, the UK simply does not have the buying power to persuade any major manufacturer to produce a one off for us where their standard safety systems are concerned. We get what the EU gets because that's the only sensible economic decision for Lexus.

As regards excuses for speeding, strictly speaking, a medical emergency doesn't give legal exception to posted limits but can be used in mitigation IF it goes to court. With proof, it's highly unlikely you'd be prosecuted unless the manner of your driving could be shown to be dangerous or without due care and consideration of other road users. Speeding, per-se, is not inherently dangerous. Lack of driving ability, or driving without due care both put yourselves and other road users at risk, so it's caveated by "If in a medical emergency you need to push past posted limits, take care and if you decide to, do so well within your ability as a driver, considering the safety of others". However, it would have to be proved it was a time critical emergency that could have serious consequences if not arriving at a hospital in time.

I only ever had recourse to this once in my life, many years ago, when an ambulance was called for a chap sharing a commercial workshop I was working in managed to introduce his hand to a 14" table saw and lost some fingers leaving splintered bones sticking from his hand. He was in shock and bleeding out badly. An ambulance was called then cancelled after 20 minutes as it was diverted to a cardiac arrest victim. On balance of risk, I helped the unfortunate chap into my car, strapped him in after bandaging up his arm and drove as quickly as safe to, to the nearest A&E. He later told me that saved his life as even a few minutes more could have proved fatal. I had a good reason, drove within my limits, drove safely but yes, had to exceed the limits a few times to get there on time. It took hours to clean up the inside of my car which was covered in blood. I did not attempt any dangerous overtakes nor shoot junctions or traffic lights but kept it sensible and safe. I never speed when on blood bike duty as we simply do not have that exception, even as advanced riders. We usually have enough time to get time critical drops done without recourse to putting ourselves or others at risk but a bike is easier to filter through queues if safe and legal to do so.

GMB · July 7

18 hours ago, Linas.P said:

if you put your car in Sport/Sport+ then it gets disabled by default

Thanks for that Linas - I did not know. However I never use sport mode ( OK maybe twice in a year just to upset some range rover drivers at the traffic lights😉) because the daft 8 speed gearbox hangs on to low gears too much. This gearbox senses that if I drive a bit more lively ( occasionally ) then it hangs on to lower gears e.g. won't change up from 4th, so I have to force it up to 8th using the paddle. I can see the logic but it is frail. This is one of the only two issues that I have with the car - the other, dare I say it -- turbo lag causing gutless whiny take offs.🫤. BTW Average fuel consumption 200t is regularly 28mpg mixed urban driving.

On the ISF the 8 speed box is impeccable.😁

Linas.P · July 7

5 hours ago, GMB said:

Thanks for that Linas - I did not know. However I never use sport mode ( OK maybe twice in a year just to upset some range rover drivers at the traffic lights😉) because the daft 8 speed gearbox hangs on to low gears too much. This gearbox senses that if I drive a bit more lively ( occasionally ) then it hangs on to lower gears e.g. won't change up from 4th, so I have to force it up to 8th using the paddle. I can see the logic but it is frail. This is one of the only two issues that I have with the car - the other, dare I say it -- turbo lag causing gutless whiny take offs.🫤. BTW Average fuel consumption 200t is regularly 28mpg mixed urban driving.

On the ISF the 8 speed box is impeccable.😁

I know all those issues too well. It has all to do with the engine. Although in my experience the Sport/Sport+ was the answer for the gearbox, yes you right - if you accelerate quickly then it hangs on gears. Kind of counterintuitively Sport/Sport+ is best mode when you want to relax and drive slowly, just makes car more responsive allowing more moderation on accelerator, whereas on Normal and god forbid Eco accelerator is like on/off switch... nothing... nothing... nothing, then it goes to red line. 28MPG is good, perhaps smaller wheels on IS helps, I was closer to 24 myself.

David1962 · September 29

Hi all, I'm looking to order an 'F Sport NX450h+' and interested in the ISA (Intelligent Speed Alert) issues as the 'beeps' were quite audible in my test drive the other day every time I went even 1mph over the speed limit.
It's something all manufacturers are doing not just Lexus but it does seem others do make it easier to disable ISA so its not such a faff turning it off for every trip. Most have a short cut button on the steering wheel or dashboard or a one touch operation on the screen.
The dealer is pretty useless at techy questions so can any owners on here please definitively answer these two questions which have been touched on in this thread;
1. How many screens or menus do you really have to go through to disable ISA for each trip?
2. Does driving in Sport/Sports+ mode really disable ISA by default as mentioned above (and I presume the car can still drive in hybrid electric mode when in Sports mode)?
Any answers gratefully received!

ShivP · October 21

On 9/29/2024 at 5:38 PM, David1962 said:

Hi all, I'm looking to order an 'F Sport NX450h+' and interested in the ISA (Intelligent Speed Alert) issues as the 'beeps' were quite audible in my test drive the other day every time I went even 1mph over the speed limit.
It's something all manufacturers are doing not just Lexus but it does seem others do make it easier to disable ISA so its not such a faff turning it off for every trip. Most have a short cut button on the steering wheel or dashboard or a one touch operation on the screen.
The dealer is pretty useless at techy questions so can any owners on here please definitively answer these two questions which have been touched on in this thread;
1. How many screens or menus do you really have to go through to disable ISA for each trip?
2. Does driving in Sport/Sports+ mode really disable ISA by default as mentioned above (and I presume the car can still drive in hybrid electric mode when in Sports mode)?
Any answers gratefully received!

Hi all, wouldalso be nice to know this... in exactly the same situation and thinking of getting a used one just to avoid this annoying feature

Xez · October 23

On 9/29/2024 at 5:38 PM, David1962 said:

1. How many screens or menus do you really have to go through to disable ISA for each trip?
2. Does driving in Sport/Sports+ mode really disable ISA by default as mentioned above (and I presume the car can still drive in hybrid electric mode when in Sports mode)?

Hi, with my RX (Gen 5) to disable the speed warning for each trip involves the following:

1. Tap Vehicle icon

2. Tap Driving Assist

3. Swipe screen left then press Customise

4. Tap Notification

5. Tap Excess Speed Notification

6. Choose Off, Visual or Audible and Visual (the default) - I choose Visual only

7. Tap OK

….then drive 😂

In answer to your second question, no Sport mode doesn’t automatically disable the beeps in my car, but you can drive in Sports mode on pure EV.

Hope this helps

ShivP · October 25

On 10/23/2024 at 3:50 PM, Xez said:

Hi, with my RX (Gen 5) to disable the speed warning for each trip involves the following:

1. Tap Vehicle icon

2. Tap Driving Assist

3. Swipe screen left then press Customise

4. Tap Notification

5. Tap Excess Speed Notification

6. Choose Off, Visual or Audible and Visual (the default) - I choose Visual only

7. Tap OK

….then drive 😂

In answer to your second question, no Sport mode doesn’t automatically disable the beeps in my car, but you can drive in Sports mode on pure EV.

Hope this helps