Pratap,
Here's is an explanation using the Toyota Prius as an example...
Why 100,000 Miles for Prius?
It has come to our attention that an Oregonian article about the
Dust-to-Dust report was light on facts, slim on details and void of any
explanations. This, in turn, turned into a bloggers' frenzy with a key
question being the life expectancy of the Prius.
To clarify:
The Prius was amortized over 100,000-plus miles for a number of reasons.
The 100,000 mile life expectancy for Prius is time as well as distance
sensitive. The historical data shows early Prius models were driven an
average of only 6,700 miles per year (rounded). At that rate, the
vehicle would require 15 years to reach 100,000 miles. It was our
determination that is highly unlikely the '05 or '06 Prius models would
still be in active service let alone serviceable 15 years from today.
The reason for this is twofold: First, the first and second generation
Prius hybrid technologies are rapidly being replaced by lighter, more
efficient systems for the new and upcoming Prius versions.
Historically, vehicles that become obsolete have a shorter life span (in
time) than existing or serviceable technology.
Second, competitive vehicles to Prius are being planned by virtually all
automakers using either Prius-like dual-mode or plug-in hybrid
technology (e.g. Chevrolet Volt). This competition, looking at the
historic context which is all we can do, is likely to drive the value of
older technology Prius models lower. We've already seen the early stages
of this happening with decreasing used values for all of the original
batch of hybrids.
At some point, economic considerations make it far more practical for
owners (or dealers who receive them in trade) to "retire" the vehicles
because a limited used-vehicle market would exist for it. Again, in
Prius's case this is time, not necessarily only mileage, sensitive.
Can the Prius be driven more than 100,000 miles? Of course. The vehicle
is superbly engineered. But this assumes the average Prius driver begins
using the car more often. If the Prius were driven the American average
of 13,000 miles per year, it would hit the 100,000 mile mark in 7.6
years, well within its attractive (financially and technologically)
useful life span. In 10 years, again about the maximum for
ground-breaking technology, it would have registered 130,000 miles.
Mechanically, there is no logical reason for the Prius not to last
130,000 miles or more.
The latest data shows Prius owners are driving more than early Prius
owners and the use of the vehicle is becoming a primary means of
transportation in a household rather than a novelty. But the average
annual mileage, outside of certain southern-tier states, remains barely
above 7,000 per year.
Other components on the Prius, such as tires, are less distance-mileage
friendly than non-hybrids of the same size and weight. For example,
surveys of Prius owners by us and other research companies show barely
16,000 miles average life for original-equipment tires compared to
43,000 for Toyota Corolla. This high-tech tire uses a compound and
design that reduces rolling resistance and thus improves fuel economy.
But the typical replacement tire for a Prius will not likely be the OEM
specialty variety, cutting both fuel economy and distance-per-battery
charge of the Prius.
As for Hummer, much of the design, development and manufacturing energy
costs are spread across more than just this single model. (One of the
original and recent Prius disadvantages, quickly being turned around.)
In addition, the platform, power train and other mechanical components
are shared with a variety of other GM products and have a significantly
longer post-disposal life in the replacement market. Higher volume of
components speeds manufacturing and reduces energy per-unit costs. Add
the simplicity of disposing of the Hummer and the entire per-mile cost
becomes lower even though the fuel economy is staggeringly worse than
Prius.
And as I pointed out in the past, the energy cost per mile is
unequivocally going to decline for Prius over time as the technology
continues to spread across other models and the disposal/scrap industry
learns how to deal with its high-tech materials and components.
-----Original Message-----
From: EnviroNet [mailto:[log in to unmask]] On Behalf Of Pratap Singh
Sent: Wednesday, June 13, 2007 2:11 PM
To: [log in to unmask]
Subject: Re: [EN] "Dust to Dust" Energy cost per mile study for
automobiles...
Gordon,
CNW marketing did not disclose the source of their funding and or the
sponsor(s) of their research. Also reading the Consumer Reports data on
auto reliability and durability for the last 20 years, it is clear that
Japanese makes outlast American made cars. In other words 'Expected Life
Miles' for Japanese cars is higher than American Cars.
My own experience with Japanese cars (Toyota Tercel, Mitsubishi Galant,
and each lasting > 200,000 miles) has been good when compared to (Ford
Econoline Van, GM Oldsmobile Cutlass, and each lasting < 120,000 miles).
This is based on average driving of 15K miles/year that is cars were
driven 13 years
(imports) vs. 8 years (domestics).
My question is based on Consumer Reports data and own driving experience
with both domestic and imported cars.
Being in the Reliability field, I welcome all opinions (true, false,
absurd, half truths....) but make decisions on valid data and analysis
and stated assumptions. It is also well known that Statistics (valid
data) do not lie; it is the liars who twist statistics (data) to support
their agenda. When one looks at the data stated in Table (pages 28- 32),
it is obvious the 'Expected life miles' of Japanese cars is lower than
American makes in most of the classes..... hmmm!! What gives? May be
some person has an explanation of this statistics. Have a good day.
pratap singh
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