Reply to: Speed Kills

[Dylan]

Maybe in your day Granddad.

If the same computer is running the dash, cruise control, monitoring the throttle input, gearbox and start/stop button, and it had crashed, then it's all believable. The only bit that isn't is the brakes.

Throttle pedal has 2 sensors that either move in opposite directions or are scaled differently, eg main 0-100% 0.2v to 4.8v, tracking sensor could be 0.1 to 2.4v for the same 0-100% range, or 4.8v down to 0.2v. Both sensors are evaluated, if the resulting values differ then it is considered a fault (no way of knowing which is the truthful sensor, if either are). If the ECU says the pedal is at 100% then it is as 100%, a bad sensor will kill the throttle.

Your assertion that the ECU had "crashed" is curious given the ECU was still running the engine. Also look up ISO26262...

On all the VAG cars I've driven brake application will also kill the throttle regardless of what is being requested by the throttle pedal.

[tomtomagain]

I reckon he deliberately killed himself.

That's what the story read like to me.

[xoggoth]

There was joke in Viz Letterbocks; if your brakes fail just release the bonnet, the resistance will slow you down. Not quite sure that works with modern cars but actually sounds sensible.

[VectraMan]

the speedometer in most cars is "mechanical" counting the wheels revolutions (that's why you have to be mindful when using non-standard tire sizes for your make/model as t affects the speedometer readings) So it's highly unlikely that he was going much faster than 70 while the speedometer was showing 70.

Maybe in your day Granddad.

If the same computer is running the dash, cruise control, monitoring the throttle input, gearbox and start/stop button, and it had crashed, then it's all believable. The only bit that isn't is the brakes.

[sal]

Him slamming his foot on the accelerator instead of the breaks for 8min could explain most/all of what happened. the question is why would he do that?

He might have been high, a lot of the "legal" highs out there are completely messing up your mind. No evidence of brakes use point that he was doing something wrong for 8 min, it's not like the old dear that accidently slammed the accelerator for a couple of seconds and trashed some cars.

'It shows 70mph but I'm going much faster'

the speedometer in most cars is "mechanical" counting the wheels revolutions (that's why you have to be mindful when using non-standard tire sizes for your make/model as t affects the speedometer readings) So it's highly unlikely that he was going much faster than 70 while the speedometer was showing 70.

To sum it up, either the breaks, the gearbox, the speedometer, the ignition key, accelerator pedal/cruise control all failed spectacularly at the same time, or there was something wrong with the driver.

[BlasterBates]

Murder is no fun. Hacking the driverless cars to take you into an unmanned automated car park and leaving you there for the night is... need to order some micro controller boards...

Reminds me of Lemmy's story about Ritchie Blackmore, who slipped his road manager a "Micky Finn" and left him naked in a hire car on a ferry to Iceland.

Apparently if he found anyone asleep he would shave off their eyebrows.

[sasguru]

Not if you don't take the key out

I reckon in his panic he was flooring the accelerator thinking it was the brake. Wouldn't be the first time that has happened. Some old dear trashed a dozen cars in a car park the other month doing the same thing.

I think there's an ECHO in here

[vwdan]

Unfortunately many modern cars are completely drive by wire. I would imagine the brakes are electronic.

.

I've never come across a normal car that's brake by wire - certainly not an Octavia. ABS and so on sit inbetween and are pretty much fail safe.

[OwlHoot]

Probably would have activated the steering lock.

Not if you don't take the key out

I reckon in his panic he was flooring the accelerator thinking it was the brake. Wouldn't be the first time that has happened. Some old dear trashed a dozen cars in a car park the other month doing the same thing.

[VectraMan]

Unfortunately many modern cars are completely drive by wire. I would imagine the brakes are electronic.

Fortunately brakes are hydraulic from the pressure from your foot. But having said that ABS can cut certain brakes, and a lot of cars have Electronic Brake force Distribution to really **** things up.

My car's due a recall because if your knee repeatedly bangs against the right part of the trim in the driver's footwell it can cause a connector to wear and ultimately lead to a power steering failure.

[VectraMan]

It says no evidence was found of braking and the accelerator was pressed until the last moment.

The accelerator is drive by wire, i.e. it's a potentiometer that the computer is reading. So just because the data says the accelerator was pressed doesn't mean it really was. In fact that backs up the story - the computer thought he was giving it full throttle.

[vetran]

Indeed - my old '68 Van had a crap accelerator linkage that got exposed to, well, everything. Ever few years it'd start seizing up which was always good fun.

I find it very hard to believe that he couldn't physically brake or otherwise stop the car, though - peculiar case.

Having read the article, it screams "honorable suicide" to me.

Unfortunately many modern cars are completely drive by wire. I would imagine the brakes are electronic.

People did mention that both an electronic fault could cause a serious crash (which is why aeroplanes have redundant circuits & manual controls) and that it would be difficult to fault find afterwards which is why aeroplanes have black boxes.Cars seem to have neither.

[sasguru]

Having read the article, it screams panic and therefore illogical action due to brain freeze to me.

FTFY.
It's surprising what happens to the human mind under stress.
It says no evidence was found of braking and the accelerator was pressed until the last moment.
Could be as simple as he thought he was pressing the brake pedal (which should have disconnected the cruise control?) but was pressing the accelerator instead.
Happens all the time with older people who are losing their marbles.
And consistent with the facts ....

[Lockhouse]

I once witnessed a unmanned runaway XJ6 speed down a residential street at 40mph bouncing off parked cars on either side of the road. It was like a Stephen King film.

[vwdan]

Another good reason to drive a manual. And a car with a proper ignition key (which mine doesn't have).

Brakes are manual though. And brakes vs engine the brakes should still win, at least until they catch fire.

I experienced a sticky throttle on my 125 on one cold winter night. That was terrifying. I guess moisture had got into the cable and frozen; so it's not necessarily electronics that try to kill you.

Indeed - my old '68 Van had a crap accelerator linkage that got exposed to, well, everything. Ever few years it'd start seizing up which was always good fun.

I find it very hard to believe that he couldn't physically brake or otherwise stop the car, though - peculiar case.

Having read the article, it screams "honorable suicide" to me.