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posted by martyb on Saturday December 08 2018, @04:26PM   Printer-friendly
from the What-harm-could-a-lie-do dept.

After VW was outed for falsifying environmental data in its cars hundreds of thousand of VW vehicles were taken off the road now sitting in storage sites. Hundreds of thousands of cars now lie in lots in the Mojave Desert, a shuttered suburban Detroit football stadium, and a former Minnesota paper mill in America alone. These vehicles are now in the open slowly breaking down with pollutants entering the environment. Is the the modern cost of corporate greed? What can we do to ensure this never happens again?


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  • (Score: 3, Interesting) by Anonymous Coward on Sunday December 09 2018, @03:15AM (4 children)

    by Anonymous Coward on Sunday December 09 2018, @03:15AM (#771772)

    > ABS is cadence braking at a far higher rate than any human could possibly achieve.

    Sort of, but you do *not* have the whole story. Deformable surfaces like gravel, slush over ice, mud over clay, possibly loose sand on pavement, all require a different braking strategy than normal hard road surfaces. Every ABS system I've tried (many, but not all), fail to distinguish these cases. The correct strategy is a *very* slow cadence, allowing time for a large wedge of the loose material to accumulate in front of each tire. This provides the best deceleration on these surfaces.

    If you just want to stop in a straight line, locking the wheels is the best strategy. If you need to do some steering, release the locked wheels long enough to steer, then re-lock up all the wheels. Often some steering is needed to stay in lane, even on nearly level surfaces, so let the wheels roll over the 'wedges" and then steer (locked wheels are like having rubber pads--no directional control is possible).

    Here in the Great Lakes, slush over ice is common. Many knowledgeable drivers either have an older "winter car" w/out ABS, or have figured out how to pull the fuse. In the worst ABS cases (which I've experienced a number of times), I can approach an intersection at 5-10 mph, start braking a hundred feet (30 meters) in advance and feel helpless as the car just rolls into the intersection.

    The most recent time it happened, a few weeks back, I was able to make a partial right turn onto the crossing street before the cross traffic got there. So, you could say that ABS was doing its job since it let me steer, but I really just wanted to STOP!

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  • (Score: 2, Interesting) by Anonymous Coward on Sunday December 09 2018, @05:11AM (3 children)

    by Anonymous Coward on Sunday December 09 2018, @05:11AM (#771817)

    You're dangerously wrong!

    > If you just want to stop in a straight line, locking the wheels is the best strategy.

    That's not true. The static friction is much lower than the dynamic friction under almost all cases, as the surface rubber softens and road material lubricates the interface. Note that rolling is static friction at any instant (contacting points stay aligned), and skidding is dynamic friction (contacting points on surfaces shift relative to each other).

    Locking the wheels is the best strategy under some conditions, but DEFINITELY not in the general case!

    Source: lots of easy to duckduckgo theory, and I've confirmed with my own force studies on bike wheels. Setup never included intentional particulate (sand, gravel) or pooled water, but results obtained for slick-wet and dry. Rubber on cement and asphalt and wood produces more backwards force in stiction than in skid.

    • (Score: 2, Informative) by Anonymous Coward on Sunday December 09 2018, @06:51AM

      by Anonymous Coward on Sunday December 09 2018, @06:51AM (#771832)

      You missed the context (on purpose?), sorry that I didn't make it painfully clear. I only meant that locked wheels are the best strategy for deformable surfaces - which was the clear topic of my post, this whole thread is in response to Runaway and his gravel road.

      What I wrote (and you quoted):
      > If you just want to stop in a straight line, locking the wheels is the best strategy.

      What I should have written:
      > If you just want to stop in a straight line on a deformable surface, locking the wheels is the best strategy.

    • (Score: 0) by Anonymous Coward on Sunday December 09 2018, @07:01AM (1 child)

      by Anonymous Coward on Sunday December 09 2018, @07:01AM (#771835)

      > ... my own force studies on bike wheels.

      Upright or recumbent bicycle? On an upright, any serious amount of braking on the front wheel leads to pitch over.

      • (Score: 2) by Reziac on Monday December 10 2018, @12:30AM

        by Reziac (2489) on Monday December 10 2018, @12:30AM (#772155) Homepage

        Braking my old Schwinn (which was heavy -- 40 pounds on the scale) on ice... had to use rear brake ONLY. Touch the front brake and the whole bike would instantly swap ends, making for an exciting ride...

        --
        And there is no Alkibiades to come back and save us from ourselves.