On Thu, Jun 09, 2005 at 02:31:53PM -0400, Rob Lipton wrote:
> at the "fleet/large number level, any, even small changes, can result in
> really huge overall savings,
A percentage change is the same whether it applies to a family or all
the cars in the US. When the number of cars being considered gets
very large, the fuel consumption differences can be mind-boggling --
but they may be just peanuts compared to the total consumption.
> and its not an either/or situation, why not
> improve things on all fronts.
Because mandating low rolling resistance tires does not improve things
on all fronts. My point was that it is optimistic to view the
benefit of low rolling resistance tires as a small change. The
benefit is significantly less than it first appears to be, because
of the composition of the cars on the road.
And the detrimental effects are tires that have less grip and/or don't
last as long. The RE92s have a treadwear of 140! How much energy is
going into producing the extra sets of tires that you'll be burning
through compared to the gas you would save? What is the environmental
impact of producing those tires?
I think the benefit is not as great as it seems, and there are costs
that may not be considered.
--
john@idsfa.net John Stimson
http://www.idsfa.net/~john/ HMC Physics '94
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