At a recent LUG meeting, we were talking about various uses for web
scraping, and someone brought up a Wikipedia game: start on any page,
click on the first real link, then repeat on the page that comes up.
The claim is that this chain always gets to Wikipedia's page on
Philosophy.
We tried a few rounds, and sure enough, every page we tried did
eventually get to Philosophy, usually via languages, which goes to
communication, goes to discipline, action, intention, mental, thought,
idea, philosophy.
It's a perfect game for a discussion of scraping. It should be an easy
exercise to write a scraper to do this, right?
Read more ...
Tags: programming, python, scraping, beautiful soup, wikipedia
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19:31 Nov 20, 2021
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We had to get two tires recently, after the Civic got a flat.
Naturally, we wanted the new tires on the front. That's where
steering and braking happens, as well as the drive wheels and
most of the car's weight ... so that's where we wanted the newer tires.
The shop (America's Tire) refused. They said it's a company policy
that a new pair of tires must always go on the rear.
They've even printed up glossy signs
explaining
their reasoning -- a fancy poster image that is, unfortunately, wrong.
They show two scenarios. In the one on the left, the rear tires are
losing traction, and the rear end of the car is sliding out. That's
called "oversteer". The car might spin, especially if the driver has
never experienced it before.
That part's all true.
The problem with their diagram is the scenario on the right, where the
presumably better tires are on the rear. In their diagram, magically all
four tires are holding -- nothing ever loses traction. Good deal!
But what really happens if you put the bad tires on the front is that
if something slips, it'll be the front. That's called "understeer".
Understeer can be just as dangerous as oversteer. With practice (I recommend
autocross!)
a driver can learn to detect oversteer and steer out of it before it
gets to be a problem. There's an old saying among racers and
performance drivers: "Oversteer is when the passenger is
scared. Understeer is when the driver is scared."
Most passenger cars, especially front-wheel-drive cars like our Civic,
are designed to understeer severely to begin with.
Putting the poorer tires on the front makes that even worse.
And don't forget the importance of braking. Most of a car's braking
ability comes from the front tires. Don't you want your best rubber
working for you in a panic stop?
While I do understand why the default might be to put new tires on
the rear -- it's better for inexperienced or panicky drivers -- to
insist on it in all cases is just silly.
We drove the Civic home and rotated the tires ourselves.
How did the policy get started?
Dave and I first encountered this policy a couple of years ago.
In the intervening years, it's become pervasive -- just about every
tire shop insists on it now. How did that happen?
If you ask at the tire shop, they may tell you that it's a federal policy --
DOT or some such agency -- or even that it's a state law.
Neither is true. It's merely company policy.
Some will also tell you that it arose from a lawsuit in which a tire
company was sued after a customer spun out. So two years ago, we went
looking to see if that was really true.
Back then, googling either "oversteer" or "understeer" led inexorably
to a Wikipedia page with a reference to "San Luis Obispo County Court
Case CV078853". Unfortunately, Wikipedia's link next to the court case
reference actually led to a general page for a law firm that appears to
specialize in vehicular personal injury lawsuits. (Nice advertising, that.)
There was no information about any such case.
Nor did there seem to be any official records online of such a case;
and the SLO courthouse didn't respond to an email request for more information.
Googling the court case, though, got lots of hits -- nearly all of them
pasted verbatim from the Wikipedia page, then using that as "proof"
of the supposed safety argument.
The test of time
Now, a few years later, it seems that nearly all tire manufacturers
have adopted this as a firm, non-negotiable policy.
Some shops are even using it as a reason to
refuse to
rotate
tires!
(See, the front tires wear faster on most cars,
so if you rotate tires between front and rear, now you're putting the
more worn tires on the rear ... which is dangerous! Better to just
let those front tires wear out and make the customer buy a new pair.)
The news is better on the Wikipedia end. Someone eventually heeded
Dave's attempt to fix the Wikipedia page, removed the bogus
advertising link to the ambulance-chasing law firm, and added
"citation needed". Subsequently,
several people rewrote the page in stages, with comments like "This is a
complete replacement. The existing version was wrong from the 1st
sentence and has little relationship to the standard terminology."
The page is much better now.
What isn't better is that the sentence from the old Wikipedia page is
still all over the net, word for word. Google for the court case and you'll
find lots of examples. Many of them are content mills copying random
Wikipedia content onto pages that bear no relation to cars at all.
But unfortunately, you'll also find lots of cases of people using
this phantom court case to argue the safety point.
Sadly, it seems that once something gets onto Wikipedia, it becomes
part of the zeitgeist forever ... and however wrong it might be, you'll
never be able to convince people of that.
Tags: skepticism, urban legend, wikipedia, cars
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19:38 Feb 19, 2012
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