- http://www.theglobeandmail.com/servl...ional/Americas

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Simple arithmetic: starting at 0.1% market penetration (that is, the percentage of cars sold each year that are hybrid), if hybrid tech doubles it's share every year, in 10 years 100% of cars sold will be hybrid.

Perhaps sending the GM exec back to the 6th grade for some remedial math will help them plan and compete a bit better.

In the same article, they write: "According to the U.S. Environmental Protection Agency, the hybrids currently available save the average driver anywhere from $300 (U.S.) to $600 a year in fuel costs. With current markups of around $6,000 to $14,000 over the base models, gas prices would have to double for most consumers to recover that initial expense."

FUD regarding the price of hybrid tech. The careful reader notes the comparison between a hybrid car, and a **base** model. What garbage.

The hybrid saves me $207 in gas a month. So 12x$207 = $2484 per year it is saving me. I don't know where EPA gets those numbers.

Karen, how did you come up with $207 ?

My calc goes like this: (1500miles/month)(gallon/50miles)($2.25/gallon)
= $68/month in gas savings.
The unspoken assumption here is an alternative car would get 25 mpg (twice the gas consumption).

http://www.mixedpower.com/modules.php?name=Gas_Savings Using this calculator with using today's gas price not the price of gas when I bought the car this was my savings - noted my car before the HCH was a Jeep Cherokee 4x4 and my commute is 140 miles a day roundtrip.

Ouput Month Year 10 Years
Gallons of Gas Saved 146 1,763 17,630
Money Saved $310 $3,720 $37,201
C02 Saved (Pounds) 543 6,523 65,234

On edit: My Jeep got around 18 mpg according to EPA estimates so all of these numbers are using EPA estimates. But really when I drove my Jeep I drove 80mph home and so probably got less than 18mpg and now with my HCH I drive 60 miles per hour home and get better than the EPA average of 48mpg. But in the calculations above I used the EPA estimates. And the current price of gas where I live is 2.11

Growth isn't exponential, though. It's logarithmic

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Err Jason, is that an inside joke I am missing out on ?

Karen, your numbers make sense. But only a minority of the population start from an suv AND drive ~ 40K miles/year.

The average driver starts from a vehicle that gets 25 mpg, and covers about 15k miles/year. If you plug these numbers into your calculator, you will see where the EPA gets it's numbers.

And particularly in your case since you chose a HCH, I would suggest a comparison to a regular Honda Civic would be reasonable. Does 45 vs 35 mpg sound about right ?
The same 15K average driver now saves 8 gallons/month by picking a HCH over a regular civic.

If the regular civic is not SULEV, then it is an apples to oranges comparison, but one many an american might make anyway.

I have said it before .. the Prius stands out because it is a BIG car that gets good mileage. Willingness to drive a conventional Civic makes the hybrid proposition much less attractive.

No joke, Eric. With limited populations (cars), growth of an attribute (hybrid) grows logarithmically, not exponentially. Think of it as a disease. There'll always be people who don't get the disease for a very long time, if at all. Even if it practically takes over the whole world. That's logarithmic.

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You are not planning to go into a math related discipline, I hope ;-)

"Doubling every year" is this function: 2^x, where x is the number of years that have passed.

It is true that in the case of car ownership, the growth has an upper bound and the doubling must level off, but that doesn't preclude a period of time where change is exponential.

I'm guessing you are thinking of curves that have an asymptope, and therefore a boundary value for the function. But a logarithm does not guarantee you an upper bound.

Consider the function y = ln(x). Can you find an upper bound ?

Likewise, power functions can be bounded. (1/x)^n looking at n from 0 to infinity has asymptopes easily discernible.

Logs and exponents are inverse functions of each other. They are both curves. And, though I am not a mathematician, I am reasonably sure they have similar characteristics.

No, no plans to go into math. But, if you're suggesting a realistic growth of hybrid share is exponential...? Hardly. Why do you reject the logarithmic model, exactly?

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