[SuperTrooper]

Lets start by defining "fleet turnover". It means adding up annual new car sales until the total surpasses the total vehicle fleet size for a given year. The size of the national fleet for 2007 was just over 252 million vehicles. On average the size of the fleet grows by 5 millions vehicles per year. In 2007 there were 15 millions new vehicles sold (an average sales year going back to 2000). Projected sales for 2008 are 12 million new vehicles. You do the math.

We have the lowest vehicle scrap rate since 1953. Indeed, from 2003 to 2006 the actual number of cars scrapped, not just the percentage, decreased. Vehicle "fads" may disappear from the front lines of auto dealers, but they linger in the fleet for years.

I think the impact of EVs is regional to a large degree. Look at how many EV firms are based on the west coast. It skews your experience. Here in the northeast NEVs actually driven on streets are truly a rare sight. The impact of winter weather on current battery technologies reduces the advantage of battery dependent vehicles for parts of the year.

I think the Volt will do just fine. If it arrives on time it will be at the forefront of the plug-in hybrid wave that will hit in 2010. It will have the advantage of near continuous press coverage since early 2007, and many people will automatically connect the Volt with the plug-in hybrid concept. Say "hybrid" today and most people think "Prius". Come 2010, if you say "plug-in hybrid" Americans will think "Volt".