

California Prius Update: Wear pattern on brakes raises doubt - MikeCapone
http://online.wsj.com/article/SB10001424052748704734304575120001542947616.html?mod=WSJ_hps_LEFTWhatsNews

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gcanyon
I'm not sure I agree with the article's conclusion, although I'm convinced the
guy is lying. The basic fact presented is that the brakes show no sign of
heavy use, but of course they don't: the brakes are more powerful than the
engine, so if they were applied heavily, the car would have stopped. But the
fact that they don't show signs of heavy use doesn't necessarily mean that he
wasn't stomping on the brake pedal. The whole point of his accusation is that
there is something wrong with his Prius.

As I said, I'm convinced he's lying, but to show that they'll need to provide
evidence that the entire braking system was working, not just that the brake
pads aren't worn down.

~~~
brianobush
Are brakes more powerful than an engine at full speed along with the car
(large mass) moving at high speed? Brakes are designed to slow a car not under
power.

~~~
adamswann
Car and Driver magazine had a great article a few months ago in which they
tested breaking several different cars (including one of the recalled Toyotas)
from 70 mph down to zero -- both with the throttle behaving normally and with
it forced to full on. In most cases, the brakes are plenty capable of stopping
the vehicle at full throttle (the exception was a 540-hp Roush Stage 3 Mustang
travelling at 100 mph with the throttle locked -- in that case, the breaking
distance was tripled to a total of ~900 feet).

[http://www.caranddriver.com/features/09q4/how_to_deal_with_u...](http://www.caranddriver.com/features/09q4/how_to_deal_with_unintended_acceleration-
tech_dept)

One of the interesting points in the article was that the Toyota Camry -- with
throttle forced wide open -- stops in a shorter distance than a Ford Taurus
without any issues.

On the other hand, the article also points out that at 100 mph, it wouldn't
have been immediately obvious that the breaks were working, even though they
were (though at 70, you would have felt an immediate effect).

~~~
sokoloff
The point curiously missing from the C&D article is that a car driving a full
throttle will also be generating only a tiny amount of manifold vacuum. In
most cars, more vacuum is necessary to provide the power-assist to the brakes,
once any stored vacuum is used up. (The brakes will work, but losing power
brakes for the average driver will be an upsetting event, especially with a
stuck throttle.) They mention "don't turn off the ignition because that will
cause you to lose brake assist", but fail to connect the no vacuum at wide
open throttle to the same end result.

I'm sure the C&D test drivers were willing to mash the pedal and generate the
best braking force the car was capable of. The average person, confronted with
a stuck throttle, lost power brakes and the resulting "hard" brake pedal may
very well not be able to summon the force required to generate full brake
pressure. (It's an amazing amount of force compared to what you're used to
using. If you're also the type to worry about flipping the car from putting
the car in neutral, you're probably not going to bend the seatback applying
enough brake pressure to get the job done.) I think I'd have expected better
than the average driver from a trained highway patrol officer, though.

~~~
blueben
You can't have it both ways. Either drivers are pushing the pedal as hard as
they can (which every single driver reports) or they aren't because they're
scared.

Either way, your argument is based on a bad assumption. At full throttle in a
non-super or turbocharged vehicle, there is still more than enough vacuum to
assist in braking.

~~~
blueben
Another point I didn't mention. The Prius can detect a no-assist situation and
will reroute all braking pressure to the front wheels for maximum
effectiveness. So even in the extremely unlikely situation you have no
regenerative braking and no vacuum assist, you can _still_ stop the car.

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S_A_P
"During the 911 call, the operator urged Mr. Sikes to shift the car into
neutral. He later said he was afraid doing so might cause the car to "flip" or
shift into reverse."

Maybe a driving test should be re-instituted every few years, or at the very
least make sure that drivers have a basic grasp of physics...

~~~
rajat
I will say that I took my Subaru out yesterday intending to try and switch to
neutral, this after hearing about this controversy, and it took a monumental
act of will to actually do it. I was really scared that I would shift into
reverse and harm my car. Finally decided to pay heed to my fears and didn't do
it until after I had tested just how much pressure it takes to do the switch
while standing still with my feet on the brakes.

I don't mean this to say that I defend Mr. Sikes, but the fact that reverse is
just one up from neutral is kind of scary. Just how careful would you have to
be to avoid doing the shift? Is there a check in the system that prohibits
shifting to reverse if the car is moving forwards?

~~~
cheald
I can't speak for the Prius, but my Grand Prix has a shifter with a button
that I have to depress to go into any gear _except_ neutral. I can just slap
at the shifter and pop it into neutral without any fear that I'd over-shift
into reverse.

~~~
baguasquirrel
I'm pretty sure that this feature is standard on every modern car that doesn't
suck (i.e. everything we have here in the States). I've yet to drive a car
that didn't have it.

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hga
Try this for full version:
[http://www.google.com/search?q=%22Interstate+8+near+San+Dieg...](http://www.google.com/search?q=%22Interstate+8+near+San+Diego.+He+eventually+brought+the+vehicle%22+site%3Awsj.com)

~~~
kgermino
Thanks, I'd like to see people start putting a [sub] tag or something similar
in the title for pages that require a subscription.

~~~
hga
You're welcome.

Although WRT to subscriptions it can get tricky. E.g. the _Financial Times_
will let you read 1? or so articles per month without registering, free
registration gets you 10? or so per month, then you have to pay.

Murdoch's _Wall Street Journal_ doesn't make it easy for a subscriber to know
which articles are directly free and which aren't: some of the news items that
are in the class of this one and some (recently fewer) of the OPED pages are
free. But if not, if you do a Google search like the one above and then click
through you get the full article, despite his grumbling about Google et. al.
Go figure.

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reader5000
I think the guy is being paid by Toyota. One dramatic case regarding this
highly publicized recall turns out to be a fraud; casts doubt on the entire
ordeal and wins the public back over to Toyota. Genius.

~~~
MikeCapone
If they were clever enough to do that, they probably would've handled the
situation better so far.

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tlrobinson
I hoping we'll find out this guy shorted large amounts of Toyota stock the day
before or works for a competing car company...

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jrockway
This article comes to an abrupt...

~~~
baguasquirrel
I feel that we should avoid submitting articles like this.

~~~
hga
See my recent comment on how a subscriber can't easily know if a _Wall Street
Journal_ article is free or not and how you can easily see all of one anyway.

