Cruise Control/Brake Failure Incident - CLA 17Reg

[Dryce]

Also brake should function normally as it's independent from cruise control, however the brake pedal is programmed to 'disengage' the cruise control. With them being linked electronically and with all our pedals communicating with a computer rather than traditional mechanical means, there is the possibility that the cruise control did in fact interfere with your CLA's braking ability.

I don't believe that after SBC deleted as a feature that MBs have brake-by-wire.

So they won't be linked 'electronically' and the braking system will still be based on 'traditional mechanical means' and it is therefore not possible that the 'cruise control did in fact interfere' with the CLA's braking ability.

The linkage between the cruise control will likely be (a) the brake light sensor. When that is activated the CC would disengage. and (b) that if it is Adaptive CC then there is an extra mechanism to allow the CC to activate the brakes. Neither should be able ti interfere with the car's braking ability.

I'm also curious to know, did the wheels continue to spin after making contact? Did the vehicle in front get pushed forward ferociously by it still being engaged in cruise control?

On a MB there would be traction control and ESP - which would stop this from happening separately from the CC.

The unfortunate news is someone is going to have to make a claim through either your wives policy or other party and in this case, it will be your wife at fault. However, there is the opportunity to have an official investigation put forward with Police, DVSA and Mercedes themselves. This will involve going to court, hiring lawyers, fees, doing lots of reading and preparing your evidence. Don't let that put you off though as you will be rewarded if they are found liable for it. Will help if you can have an engineer look over your vehicle to identify and confirm that Cruise Control was defective... Also, do not send it to MB for repairs by any means as they may destroy evidence that it was in fact defective, just a thought!

Logically it would be the brakes that were defective - regardless of the condition of the CC.

Also - regardless of blame - you might care to calculate the cost of the claim to the OP's spouse if they don't gro though all of this - as opposed to taking it on the chin and potentially losing NCB and paying incrsased premiums - just how much do you think "This will involve going to court, hiring lawyers, fees, doing lots of reading and preparing your evidence" would actually cost?

I think the advice to give would be to talk to the insurer about a possible fault in the car and persuade them to put a toe in the water by getting the car examined by somebody suitable to assess it technically - and then determining a strategy based on the results of that examination.

 

[renault12ts]

This is crazy, can't believe it would happen in 2018 on any modern day vehicle, let alone it being a Mercedes! Cruise Control technology was being developed right from the 1950's! Can you give us on a scale of 1-10 how sure you are that your wife tried to disengage cruise control with brake pedal? If it's true then I have completely lost faith in Mercedes. I wouldn't even compare Mercedes to Kia and I'll never ever recommend any new Mercedes to family and friends..

Do you have enemies that would come to your house and tamper with your brakes/brake pipes etc? Just asking as I've heard people do this. It should be obvious if anything like this was done..

Also brake should function normally as it's independent from cruise control, however the brake pedal is programmed to 'disengage' the cruise control. With them being linked electronically and with all our pedals communicating with a computer rather than traditional mechanical means, there is the possibility that the cruise control did in fact interfere with your CLA's braking ability.

I'm also curious to know, did the wheels continue to spin after making contact? Did the vehicle in front get pushed forward ferociously by it still being engaged in cruise control?

The unfortunate news is someone is going to have to make a claim through either your wives policy or other party and in this case, it will be your wife at fault. However, there is the opportunity to have an official investigation put forward with Police, DVSA and Mercedes themselves. This will involve going to court, hiring lawyers, fees, doing lots of reading and preparing your evidence. Don't let that put you off though as you will be rewarded if they are found liable for it. Will help if you can have an engineer look over your vehicle to identify and confirm that Cruise Control was defective... Also, do not send it to MB for repairs by any means as they may destroy evidence that it was in fact defective, just a thought!

Wow, slow down. You are making, as you would say, crazy assumptions based on...what? The answer in post #21 is more than correct.

 

[Quackers]

Surely autonomic braking can't rely solely on a functioning brake light switch?
Please tell me there's something a little more failsafe than that!

Several years ago Ford cars were smashing into things at full chat on an uncommanded CC acceleration.
Ford said No, No, No that can't happen and we know nothing about it.
Actually not only did they know about it they had film of their own engineers trying to stop the car from spinning its back wheels by brake pedal pressure alone. He couldn't manage it for quite some time. Lots of people could not have brought the same pressure to bear as he used - they had instruments to measure it.
They eventually said that it did happen and they put it down to spurious electrical signals under the bonnet causing the uncommanded CC acceleration. I suspect they were guessing.

Imagine a failed brake light switch joining up with an uncommanded CC acceleration and no way to brake hard enough.
Scary.

 

[MancMike]

FYI the assisted brakes are always backed up by unassisted braking. It's not "brake by wire".

Turn your engine off, and fully press the brake pedal, it should go to the floor with enough force, as it'll still have enough pressure in the system. Then try a few more times. You'll feel the pressure quickly fade, and then you've basically got brakes without any assistance, and you'd have to stand up on the brake pedal to do any meaningful braking, but it is still there.

 

[Quackers]

Well it's not brake by pedal pushing if a computer/radar sensor is doing it, is it?

 

[Dryce]

Surely autonomic braking can't rely solely on a functioning brake light switch?
Please tell me there's something a little more failsafe than that!

You're possibly misunderstanding the relationship.

When you press the brake pedal you cause the brakes to apply.

When you press the brake pedal you usually also cause the brake light to illuminate. So the pedal also causes a switch to operate when it is depressed.

There is no dependency that requires the switch to be activated in order for the brakes to be applied. It is just a simple mechanism that provides a signal that the pedal has been depressed. That signal can be shared so that it doesn't just activate the brake light but also signals the pedal has been depressed to other systems such as the CC.

 

[Dryce]

Well it's not brake by pedal pushing if a computer/radar sensor is doing it, is it?

Well yes it is if the pedal directly activates the brakes.

The CC system or other override can also activate the brakes - possibly limited. BAS systems have been around for at least 20 years (MB had them in the mid 90s). ABS can modulte the brakes and has been common for over 20 years. And servo assistance has been around for a lot lot longer.

 

[Quackers]

I appreciate that the brake switch doesn't need to work to apply the brakes
However, should that switch fail then how does the CC "know" that it's been cancelled, when you touch the brakes?
My point was more that if the CC in some way gets an uncommanded acceleration (as has happened above with the Fords) and if the brake switch is unable to turn off the CC acceleration (as it should) then it would be extremely difficult to stop the car.

Under autonomic braking the pedal is not used by the system, surely.

 

[MancMike]

Well it's not brake by pedal pushing if a computer/radar sensor is doing it, is it?

The OP states the brake pedal was pressed.

The brakes outrank the engine massively. It wouldn't be "extremely difficult". You're talking bollocks.

 

[Quackers]

Oh dear. We're talking about different sets of circumstances. Try reading my other posts - or don't, if you prefer.

 

[shyam27]

Wow, slow down. You are making, as you would say, crazy assumptions based on...what? The answer in post #21 is more than correct.

Hi, I'd just like to point out that I was waiting on some confirmation from this guy as to how sure he was that his wife tried all she can to stop the car. As I said, IF IT'S TRUE, then I have completely lost faith in Mercedes. I'm entitled to that much ain't I? In this instance, it is then not an assumption at all.

I mean I'd be inclined to believe (now this is an assumption) that she really was pressing the brakes if there is clear footage of her panicking saying the car won't slow down before the impact. I would only take the things I said on board if he was certain that she tried to disengage CC using brakes. Someone else has already mentioned there was an incident very similar to this in China, ref: Mercedes' cruise control 'gets stuck' at 75mph in China | Daily Mail Online

And then I found it's not the most uncommon thing amongst German automobiles, it also happened to this guy: Driver told 999 his cruise control was stuck as he hit speeds of 119mph, inquest hears

This poor guy has joined our community to seek some advice/help and see if anyone else has experienced anything similar so that he can elaborate in his statement of events. I think the last thing he needs is us questioning and doubting him. In my empathy, even I feel slightly bad questioning how sure he is. But at the end of the day, he seems sincere in speaking with people who've come across similar issues as it must have been shocking for him.

You guys are welcome to take it with a pinch of salt as no one was hurt, but had she set it at a higher speed then I'd hate to think what else could have happened. When your paying top dollar for an automobile, you'd expect it to have proper functioning cruise control.

 

[renault12ts]

Hi, I'd just like to point out that I was waiting on some confirmation from this guy as to how sure he was that his wife tried all she can to stop the car. As I said, IF IT'S TRUE, then I have completely lost faith in Mercedes. I'm entitled to that much ain't I? In this instance, it is then not an assumption at all.

I mean I'd be inclined to believe that she really was pressing the brakes if there is clear footage of her panicking saying the car won't slow down before the impact. I would only take the things I said on board if he was certain that she tried to disengage CC using brakes. Someone else has already mentioned there was an incident very similar to this in China, ref: Mercedes' cruise control 'gets stuck' at 75mph in China | Daily Mail Online

And then I found it's not the most uncommon thing amongst German automobiles, it also happened to this guy: Driver told 999 his cruise control was stuck as he hit speeds of 119mph, inquest hears

This poor guy has joined our community to seek some advice/help and see if anyone else has experienced anything similar so that he can elaborate in his statement of events. I think the last thing he needs is us questioning and doubting him. In my empathy, even I feel slightly bad questioning how sure he is. But at the end of the day, he seems sincere in speaking with people who've come across similar issues as it must have been shocking for him.

You guys are welcome to take it with a pinch of salt as no one was hurt, but had she set it at a higher speed then I'd hate to think what else could have happened. When your paying top dollar for an automobile, you'd expect it to have proper functioning cruise control.

You don't do logic do you? Read post #21. Brakes are stronger than engine. If she hit the brakes the car would have slowed and then stopped. No ifs or buts.

As for the story you quoted the significant part was:

"That data revealed the Skoda was travelling at 116mph with the accelerator pedal fully depressed five seconds before the crash, the inquest heard.

No braking was recorded but the hearing heard there was evidence of small steering left and right".

Still think the car was to blame?

The story from China...absolute nonsense.

 

[shyam27]

You don't do logic do you? Read post #21. Brakes are stronger than engine. If she hit the brakes the car would have slowed and then stopped. No ifs or buts.

As for the story you quoted the significant part was:

"That data revealed the Skoda was travelling at 116mph with the accelerator pedal fully depressed five seconds before the crash, the inquest heard.

No braking was recorded but the hearing heard there was evidence of small steering left and right".

Still think the car was to blame?

Yes and OP suggests brakes did not help stop the car? ''the brakes failed to stop or even slightly reduce the speed of the car, and caused my wife to crash into the car ahead at 50mph,'' The bottom line is, if OP's wife did press the brakes, why did the car not slow down/stop? And why did the CC not disengage sooner? And you say I don't do logic. Your assumption is based on OP being a liar.

''The inquest heard that the main car part that recorded the data was destroyed in the collision but it had fed the information to the vehicle's airbag system.

That data revealed the Skoda was travelling at 116mph with the accelerator pedal fully depressed five seconds before the crash, the inquest heard.

No braking was recorded but the hearing heard there was evidence of small steering left and right.''

The main part that recorded the data was destroyed, maybe the bit that records whether brakes were pressed???????

I don't think asking me if I do logic really helps the situation bud, keep those miserable thoughts to yourself, they're not constructive at all. You shouldn't take it so personally when someone attacks a 'brand', all it is is a status symbol. Don't lose your soul to that materialism fella!

 

[renault12ts]

This is not about brand loyalty...bud/fella. The first story was about a Skoda.

If the brakes are mechanical and not connected to CC then if she had pushed them the car would have slowed...as I said, there is no argument about this.

Try it yourself, keep your foot on the accelerator at 50 mph and push the brake with your left foot...the car will slow down to a stop.

If you prefer Daily Mail type stories that's your prerogative, but don't state it as fact.

 

[shyam27]

This is not about brand loyalty...bud/fella. The first story was about a Skoda.

If the brakes are mechanical and not connected to CC then if she had pushed them the car would have slowed...as I said, there is no argument about this.

Try it yourself, keep your foot on the accelerator at 50 mph and push the brake with your left foot...the car will slow down to a stop.

If you prefer Daily Mail type stories that's your prerogative, but don't state it as fact.

Don't prefer Daily Mail, but it was first British article that popped up on the event. All media outlets controlled by zionist jews anyways.

Okay, and I agree with that. That's why I asked him to confirm how sure he was initially before I was slandered by yourself.

The bit that bothers me is that, she could have pressed brake all the way down to stop vehicle or she could have dabbed the brake slightly to disengage the CC. And in the case of an emergency, please just press the brake all the way down and your car should stop! The problem I have is that this lady, worst case scenario, would have only dabbed the brake to disengage CC. After spending all that money on this motor, why did it not disengage the CC as she expected it to? You'd expect this sort of feature to work without too much expectation.

But it's fine, if your happy paying all that money and happy to live with faulty CC's that don't respond then don't have a problem with it. Your entitled to your own expectations and opinions just as I am. I'm just saying, I'd personally have a problem with it, and for me, it would ruin the brand.

 

[Dryce]

I appreciate that the brake switch doesn't need to work to apply the brakes
However, should that switch fail then how does the CC "know" that it's been cancelled, when you touch the brakes?
My point was more that if the CC in some way gets an uncommanded acceleration (as has happened above with the Fords) and if the brake switch is unable to turn off the CC acceleration (as it should) then it would be extremely difficult to stop the car.

The brakes are designed to be powerful enough to overpower the car engine.

Under autonomic braking the pedal is not used by the system, surely.

Yes.

There will be a mechanism apply the brakes by providing hydraulic pressure which is separate from the pedal. So that is additional to any action of the pedal. It may be setup to only provide limited braking - compared with what the driver can apply using the pedal.

The automotive industry is quite conservative - so the interaction of these different systems and their failure modes are well thought out.

 

[Petrol Pete]

Does the car have CPA or CPA Plus? If the sensor system worked (as evidenced by the beep) and it has CPA Plus then the obvious question is why didn't the autonomous braking kick in?Make sure you keep the dash cam footage safe. Depending upon how MB UK respond, you may need to make a report to the Driver and Vehicle Standards Agency (DVSA) and the footage could be important to their investigation.

Agreed. Do NOT leave this up to Mercedes Benz to investigate. Get an independent expert on it. Thankfully no one was seriously injured,but it could have been much worse.

 

[MercedesDriver]

This is crazy, can't believe it would happen in 2018 on any modern day vehicle, let alone it being a Mercedes! Cruise Control technology was being developed right from the 1950's! Can you give us on a scale of 1-10 how sure you are that your wife tried to disengage cruise control with brake pedal? If it's true then I have completely lost faith in Mercedes. I wouldn't even compare Mercedes to Kia and I'll never ever recommend any new Mercedes to family and friends..

Reading OPs opening post he believes his wife 100% (as I would) so it should be 10 in your scale of sureness.
If this is the reason for loosing the faith in MB then you should move on, sell your car and take a bus or walk.
Don’t buy another car, all have some sort of electronics installed.

Do you have enemies that would come to your house and tamper with your brakes/brake pipes etc? Just asking as I've heard people do this. It should be obvious if anything like this was done..

I also heard that in the USA they have some “Area 52” where aliens live. Wow, what is next, invasion by their cousin aliens?

 

[Petrol Pete]

Re: Airbags, its probably a good thing they didnt deploy, they can cause temporary deafness, burns and broken bones (eg nose). plus they generally will write a car off once they have been fired.

Been there, done that. the one that went off below the steering wheel gave me 'carpet burns' through my jeans ! the others just smacked me in the face and on the side of my head, 'dust' everywhere. Quite a shock to the system ...but better than not having them go off.

Oh, and you are correct, once airbags go off the car is usually written off. 5 went off in my crash..and the car had only 3 wheels left on it so that didn't help either.

It was a hire car so I got a new one a few hours later and was on my way.

 

[Deleted member 126251]

Lots of speculation here.....

Let me add to it. Surely these modern cars have redundant systems & fail safes ....I seem to recall that even in the olden times (when I started driving and cars were a lot simpler), the cars had dual hydraulic lines so that if one was damaged, you'd still be able to stop the car.

I'd be surprised if the op's issue was not down to human error.

Manufacturers do 10s of 1000s of hours testing their systems and being able to stop the car under any circumstance is probably one of their top priorities.

I'm following this thread ......be interested to know the outcome.