
Volvo accidentally smashes new car in safety demo - shrikant
http://www.wired.co.uk/news/archive/2010-05/07/video-volvo-accidentally-smashes-new-car-in-safety-demo
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sokoloff
Mercedes had a crash during a demonstration of Distronic a few years back as
well: [http://www.mbworld.org/forums/w211-amg/128286-distronic-
demo...](http://www.mbworld.org/forums/w211-amg/128286-distronic-demo-gone-
wrong.html)

I interned at Mercedes's advanced vehicle group in college. The culture was
very safety conscious and the bias in developing driver aids was "Minimize the
chance that your system will cause or increase the severity of collisions as
compared to if your system wasn't there."

~~~
mst
Which nicely shows what is pretty much a fundamental rule of thumb - adding
complexity to a system has to be carefully managed to ensure that the end
result is going to perform better on average than the simpler version would
have done.

I'm reminded somehow of caching overly aggressively and the resultant code
spending more time in the cache logic than it saves through not having to do
the calculations.

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matthavener
While a non-programmer might think "geez, it should have stopped, it was going
to hit that truck!", I can only think how complex the system must be to detect
an oncoming collision and brake only when necessary. I'm sure they could tune
it to be more sensitive to oncoming objects, but I'd rather defer to the drive
in those circumstances..

~~~
dagw
The story I've read was that it wasn't a problem with their the collision code
as such, but that the car battery died completely shortly before the demo and
the computer systems didn't start up right when the battery got recharged.

~~~
gvb
Draining the battery could be argued as "human error", but it is a pretty
common error.

There is no "human error" in the "computer systems didn't start up right" half
of the excuse. That is a design error.

Having said that, I've worked with avionics. Avionics power systems are
absolutely horrible with respect to voltage regulation and glitches. The power
source is switched between a ground cart, APU, and multiple engine generators
at various times and causes glitches each time. Creating hardware and software
that is able to start reliably when hit by multiple glitches with random
intervals and random duration plus power brownouts and surges is _extremely_
difficult. We used a programmable power supply that was able to do random
glitches (it was affectionately known as the "widow maker" because the
engineers' wives would become a virtual widows while the engineers worked out
the bugs ;-). When the systems engineers would assure us we would have clean
power, guaranteed, we would just roll our eyes and roll over the widow
maker... (The battery bus actually _is_ reliable and glitchless, but only
flight critical hardware gets to hook up to that.)

Just to complicate life, power glitch testing (and brake system safety
testing) is an instance of the halting problem.
<http://en.wikipedia.org/wiki/Halting_problem>

~~~
Retric
IMO, there are more fundamental problems.

Run any computer system long enough and you _will_ get random bit errors in
both memory and computation. Avionics systems mitigate this though redundant
systems but cars are not built to that level of safety. So yes, assisted
braking systems will fail. The real question is how often and to what result.

~~~
timthorn
I am led to understand that ABS systems often do have multiple independent
microcontrollers.

~~~
JshWright
I know of very few cars with multiple rotation speed sensors on the wheels
(and the system has to know the rotation speed of each wheel if the system is
to function properly). So each sensor (and all the associated cabling, wire
harnesses, etc) is a single point of failure.

ABS systems are far from fail-proof...

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jacquesm
Actually, watching this is really good, it shows you how much energy is
present in a relatively low speed collision.

One down for the demonstration effect.

~~~
hugh3
There's no shortage of crash test videos out there, though. It is, however, a
good demonstration of the safety of a modern Volvo that there was no damage
beyond the A pillar.

Compare to this rather disturbing crash test of a Chinese car:

<http://www.youtube.com/watch?v=PHZqcKj7jNM>

~~~
cubicle67
Compare that to an F150
[http://www.youtube.com/watch?v=lB0araA0T_k&feature=relat...](http://www.youtube.com/watch?v=lB0araA0T_k&feature=related)

Not at all what you'd expect. or is it?

~~~
jacquesm
Hm, when living in Canada I had one exactly like that, it really bugs me how
fragile that thing is. I always figured my biggest risk was a roll-over, now
I'm thinking the biggest risk might have been hitting a tree.

Incredible the deformation.

~~~
zokier
Afaik deformation is good, as it absorbs energy instead of delivering it to
the people inside

~~~
hugh3
Deformation of the front of the car is exactly what you want. Ideally
everything in front of your feet should be crushed like crazy. But what you
see in the Brilliance and the F-150 is that the passenger compartment itself
starts deforming, increasing the chances that you're going to wind up with a
jagged piece of door metal in your skull, or crushed between the roof and the
floor. Nasty.

After viewing the F-150 video I was tempted to say that standards must be
different for trucks -- they're built differently and have a helluva lot more
momentum to dissipate coming from the back. But then I looked at crash tests
for the Chevy Silverado and Nissan Titan, and it looks like that F-150 is just
a piece of junk because those other two hold up a lot better.

~~~
Elepsis
Let's keep in mind that we're comparing a 2001 car with much more recent ones.
Here's a video of the 2008 F-150, where it holds up dramatically better.

[http://www.youtube.com/watch?v=1LkAzt_0qIg&NR=1](http://www.youtube.com/watch?v=1LkAzt_0qIg&NR=1)

Progress is awesome.

~~~
hugh3
Found in a related video:

[http://www.youtube.com/watch?v=3ReZ0C_UF-8&feature=relat...](http://www.youtube.com/watch?v=3ReZ0C_UF-8&feature=related)

This is why an F-150 is still a pretty good place to be in a real-world
accident where you're more likely to hit another car rather than a thick
concrete wall. Conservation of momentum says that when a big heavy thing meets
a much smaller thing the big heavy thing comes off looking much better.

~~~
harpastum
That's actually not exactly what's happening. The force on each of the cars is
identical, but the major difference I see is that the F150 is actually much
taller than the escort. The grill/engine of the truck hit the car above its
center of gravity.

All of the impact energy went into the truck's engine block, but into the
passenger pillar in the car. That's why the car came off looking so much
worse.

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dcurtis
What would have happened if the collision avoidance system malfunctioned and
slammed on the brakes while you were driving fast on the highway, causing an
accident?

I am kind of scared to give software control of critical aspects of my car. Do
they test this stuff as well as the space shuttle software?

~~~
_delirium
I have some similar sentiment, but at the same time, I wonder if it's a
psychological issue? In theory, I should be willing to accept even flawed
software, _so long as_ the likelihood and severity of any flaws are less bad
than my own. And humans are not actually all that good at avoiding car
accidents, as the rather appalling crash statistics point out, so the bar
isn't even all that high for "well, at least it's better than humans"
software.

~~~
hugh3
Yes, but this system seems to be worse than my driving. For instance, I
wouldn't have hit the back of that goddamn truck.

~~~
ugh
How do you come to that conclusion? With the information we have it seems to
me that this system can’t make your driving any worse. It’s a emergency
system, it’s supposed to only kick in when you already failed. It too failed
in this case, but that only means that with or without the system, sometimes
you are dead either way.

This system doesn’t even want to be autonomous which means that if the worst
thing is does is flat out fail (and not, say, misfire) it’s no better but more
importantly also no worse than a car without the system.

~~~
tomjen3
I theory you are right, but I fear that drivers don't pay so much attention to
their driving, since "after all the computer will do it for me".

There has been a fascinating linked posted a couple of times to a story about
a guy who worked on the London road system: each time he would clear out
congestion issues, more cars would go on the road - which meant that the
average speed didn't change. He argued (or the article did, can't seem to
recall whom) that people had a specific level of risk they were prepared to
accept: make it safer than that, and people drove less safely.

~~~
MikeCapone
> He argued (or the article did, can't seem to recall whom) that people had a
> specific level of risk they were prepared to accept: make it safer than
> that, and people drove less safely.

Tom Vanderbilt also writes about this in his book "Traffic". I recommend it to
anyone interested in the psychology of driving and road design.

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thirdusername
At least Volvo aren't claiming they are the safest car in the world in Sweden
anymore, after our courts ruled it was non-verifiable:
<http://www.thelocal.se/25492/20100312> :)

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saetaes
I can't tell if it's just the angle of the video, but it doesn't look like the
airbags deployed. Maybe they were intentionally disabled, but yikes, seems
like a car you should stay away from until they work the bugs out.

~~~
MikeCapone
If I understood what I read correctly, the car came out of the gate at 30 MPH.
It hit the truck a bit slower than that, it seems. Airbags might be set not to
deploy under a certain speed because there might be more risks from the
airbags themselves than from the crash below a certain velocity.

~~~
hugh3
Alternatively this may be a prototype with airbags disabled for some reason.
Frinstance if you're going to remote-control a car you'd probably wind up
fitting something over the steering wheel, so you'd probably disable the
airbags for that.

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js2
Direct link to video <http://www.youtube.com/watch?v=QJ6z3IArINI>

