Man killed because his cruise control wouldn't switch off!

[AMG Merc]

TooMany2cvs said:

TLandCruiser said:

Also abs does not shorten braking distances, it allows the car to be steered whilst braking.

Compared to unlocked brakes, stopping distances are longer, yes.
But compared to locked brakes, they're much shorter.

Agree. Of course ABS reduces braking distances!

[LaurasOtherHalf]

Northern Munkee said:

Not sure if this has been posted already.

"In the summer and fall of 2009, hundreds of Toyota owners came forward with an alarming allegation: Their cars were suddenly and uncontrollably accelerating. Toyota was forced to recall 10 million vehicles, pay a fine of more than $1 billion, and settle countless lawsuits. The consensus was that there was something badly wrong with the world’s most popular cars. Except that there wasn’t. What happens when hysteria overtakes common sense?"

But this podcast covers most of this https://itunes.apple.com/gb/podcast/revisionist-hi...

Edited by Northern Munkee on Wednesday 14th December 21:31

Very interesting, thanks for that.

[blueg33]

AMG Merc said:

TooMany2cvs said:

TLandCruiser said:

Also abs does not shorten braking distances, it allows the car to be steered whilst braking.

Compared to unlocked brakes, stopping distances are longer, yes.
But compared to locked brakes, they're much shorter.

Agree. Of course ABS reduces braking distances!

I have seen demonstrations that show on a dry road locked brakes stop the car in a shorter distance than abs.

But I suspect that there are so many variables in terms of tyres, road surface, driver that abs provides a more consistent result

There is no doubt that most people do not push the brake pedal hard enough. I did an driving course a few years ago and amongst various things they taught us to brake properly, do threshold braking etc.

With abs they had us braking so hard it actually hurts your leg in terms of pressure on the pedal. 4 consecutive stops was knackering.

Most interesting though was 2 wheels on dry surface and 2 on a wet surface, with and without esp

[AMG Merc]

blueg33 said:

There is no doubt that most people do not push the brake pedal hard enough.

Totally agree, have read many reports about this and I think there's even mention of it in one of my AMG manuals too.

We all instinctively press the stop pedal too softly thinking something will happen (like a skid) - when in reality the braking system's been designed to do its job perfectly with a very forceful press of the pedal.

[superlightr]

blueg33 said:

AMG Merc said:

TooMany2cvs said:

TLandCruiser said:

Also abs does not shorten braking distances, it allows the car to be steered whilst braking.

Compared to unlocked brakes, stopping distances are longer, yes.
But compared to locked brakes, they're much shorter.

Agree. Of course ABS reduces braking distances!

I have seen demonstrations that show on a dry road locked brakes stop the car in a shorter distance than abs.

But I suspect that there are so many variables in terms of tyres, road surface, driver that abs provides a more consistent result

There is no doubt that most people do not push the brake pedal hard enough. I did an driving course a few years ago and amongst various things they taught us to brake properly, do threshold braking etc.

With abs they had us braking so hard it actually hurts your leg in terms of pressure on the pedal. 4 consecutive stops was knackering.

Most interesting though was 2 wheels on dry surface and 2 on a wet surface, with and without esp

Ive tried the Don Palmer wetter the better course with the high grip/low grip straddles as well- very interesting !

Edited by superlightr on Thursday 15th December 11:31

[AMG Merc]

When talking about ABS's effectiveness I do mean in the WET (as designed). If those saying without ABS is less stopping distance then they must be applying the cadence braking technique (ie: human ABS) surely?

[otolith]

superlightr said:

Ive tried the Don Palmer wetter the better course with the high grip/low grip straddles as well- very interesting !

Did the same thing at Prodrive - two wheels on tarmac, two wheels on skid surface, hands off the wheel and brake hard.

[don4l]

blueg33 said:

I have seen demonstrations that show on a dry road locked brakes stop the car in a shorter distance than abs.

I did a driving course at Millbrook that included emergency braking on a wet, polished concrete, surface.


Braking distance was much shorter with ABS than without. IIRC, abs halved the stopping distance.

[snowandrocks]

xjay1337 said:

Ayahuasca said:

FFS we have covered this one already. There are some modern cars where the pedal moves.

How modern? Nothing designed in this century will do that I'm sure.

Our Honda Accord does it for sure, 2004 car launched in 2003. The 2.0 litre cars have a conventional throttle cable while the 2.4 and diesel models are drive by wire.

[Jobbo]

blueg33 said:

I have seen demonstrations that show on a dry road locked brakes stop the car in a shorter distance than abs.

I'd be surprised if *locked* brakes stop the car faster. I do recall a skilled driver beating early ABS systems on a dry road with threshold braking.

Not sure that's at all possible now, though. You'd have to have the ability to control each wheel's brake individually through just the one brake pedal to beat an up to date ABS system

[TooMany2cvs]

Jobbo said:

I'd be surprised if *locked* brakes stop the car faster.

On some loose surfaces, where a "wedge" builds up - gravel, some snow, that sort of thing. But that's about it.

[RB Will]

Super Slo Mo said:

when you press the brakes on a Skoda it generally shuts the throttle off.

After reading this I thought I had better confirm. Took the VRS out last night and tried resting my foot on the brake while accelerating and you are right it cuts the throttle, which goes to explaining why it stopped quite so hard when I first tried it!
It doesnt require much brake to make this happen either. I could get it to accelerate with a very light brake applied but anything approaching normal braking shut the throttle down. I think there must be somehting like a 0.5 sec delay on this system as I can heel toe on a fun drive with no problems so it lets me rev while the brake is solidly applied.

I then took the OHs Mini Cooper S out to see if it did the same, it didnt cut the throttle. Similar bhp to the VRS and hard in 2nd gear it was a bit more effort to stop, you could definitely feel the brakes having to work against the engine but it did still stop the car harder than you would in normal driving and the brakes on that are a lot smaller and 12 years older design than the VRS.

I also tried something with the cruise in the VRS. Having seen people suggest maybe the cruise was stuck on. I set the cruise and used the controller on the stalk to accelerate , holding the button down. I then pressed the brake with the accelerate button still held down. The braking cancelled the cruise and it did not resume after release of the brake even with my finger still asking it to speed up.


So I'm still thinking its a setup or he is the most unluckly bloke ever with all sorts of systems failing on the car all at once and managing to hang onto it for 8 mins / over 10 miles then crashing into the one of hundreds of things he will have passed that was a guaranteed kill.
with 2-3 lanes of empty road you could have slowed it a lot by weaving and gradually increasing the steering to keep slowing the car until safe to crash or just have it going round in circles. May have taken some balls to get that started at 100+mph though lol.

[Jobbo]

TooMany2cvs said:

On some loose surfaces, where a "wedge" builds up - gravel, some snow, that sort of thing. But that's about it.

Yes, I remember that Audi advert too. But it was from over 30 years ago and I bet even loose surfaces aren't a problem for ABS now.

[FunkyNige]

AMG Merc said:

Totally agree, have read many reports about this and I think there's even mention of it in one of my AMG manuals too.

We all instinctively press the stop pedal too softly thinking something will happen (like a skid) - when in reality the braking system's been designed to do its job perfectly with a very forceful press of the pedal.

Don't most modern cars have an 'Emergency Brake Assist' type fucntion where you if you hit the brake 'quite hard' it puts them on full for you?

Quick Google brings up a pretty picture of it working

[TooMany2cvs]

Jobbo said:

TooMany2cvs said:

On some loose surfaces, where a "wedge" builds up - gravel, some snow, that sort of thing. But that's about it.

Yes, I remember that Audi advert too. But it was from over 30 years ago and I bet even loose surfaces aren't a problem for ABS now.

It's basic physics, rather than electronic sophistication. A loose surface locks quickly and easily - long braking distance if you don't let it lock. But let it lock, and effectively shove a big wedge under the front of each tyre, you stop quickly.

[otolith]

TooMany2cvs said:

It's basic physics, rather than electronic sophistication. A loose surface locks quickly and easily - long braking distance if you don't let it lock. But let it lock, and effectively shove a big wedge under the front of each tyre, you stop quickly.

Yes, the change with technology might be the system's ability to detect that was happening and react accordingly. No idea whether any systems have that capability.

[otolith]

don4l said:

I did a driving course at Millbrook that included emergency braking on a wet, polished concrete, surface.

Braking distance was much shorter with ABS than without. IIRC, abs halved the stopping distance.

While I think that is probably generally true, to be fair I'm not sure a car with ABS disabled is comparable to one which was never meant to have it and was set up accordingly. My Saab was very squirrely under hard braking when the ABS stopped working, far more so than any non-ABS car I remember.

[Sheepshanks]

RB Will said:

After reading this I thought I had better confirm. Took the VRS out last night and tried resting my foot on the brake while accelerating and you are right it cuts the throttle, which goes to explaining why it stopped quite so hard when I first tried it!
It doesnt require much brake to make this happen either. I could get it to accelerate with a very light brake applied but anything approaching normal braking shut the throttle down. I think there must be somehting like a 0.5 sec delay on this system as I can heel toe on a fun drive with no problems so it lets me rev while the brake is solidly applied.

I'm sure my Merc works on something I've seen described as a "last good input" basis - ie if you brake while the accelerator is pressed then it'll cut the gas. However if you press the brake, and then press the accelerator, then the accelerator will work. If this is correct, it would explain why your heel and toe works.

[ging84]

I tested it in my diesel merc a few weeks back, it's a bit older and clearly didn't have any think which will cut the throttle, there was a lot of noise and diesel smoke as it tried it's hardest shifting down through the gears as it slowed down, but even with 500Nm of peak torque it barely made a difference vs probably equivalent of 2000Nm+ constant available from the brakes, i really didn't need to brake very much harder than normal to slow the car.
If i had gone all the way to a stop it might have got a little bit harder as it dropped into 2nd or 1st gear, but i didnt fancy putting that load on my transmission or completely stopping on a dual carriageway, even if it was pretty much empty at the time.

[Zod]

don4l said:

blueg33 said:

I have seen demonstrations that show on a dry road locked brakes stop the car in a shorter distance than abs.

I did a driving course at Millbrook that included emergency braking on a wet, polished concrete, surface.


Braking distance was much shorter with ABS than without. IIRC, abs halved the stopping distance.

've done Milbrook, Prodrive and several BMW courses at German and Austrian circuits (I'm still no good) and all have shown the same. They have also all made the point that most drivers simply don't brake hard enough.