For a few years now, hybrid sales have been stalled at 2 to 3 percent of the U.S. market.

But for the first seven months of this year, the total is at the low end of the scale: Hybrids represented 2.06 percent of sales from January through August, and just 1.98 percent of sales in August alone.

The top three best-selling hybrids since January are:

2011 Toyota Prius

2011 Toyota Prius

  • Toyota Prius: The quintessential hybrid, the mid-size five-door hatchback Prius has been the best-selling hybrid in the States for many years.
    2011 EPA ratings: 51 mpg city, 48 mpg highway, 50 mpg combined

  • Honda Insight: The subcompact five-door hatchback Insight is the cheapest hybrid on sale in the U.S., but its sales have never come close to Honda's original plans. (Changes are coming for 2012.)
    2011 EPA ratings: 40 mpg city, 43 mpg highway, 41 mpg combined

  • Hyundai Sonata Hybrid: Like the rest of the Hyundai lineup, the new mid-size 2011 Sonata Hybrid sedan sells well and is perceived as good value for money.
    2011 EPA ratings: 35 mpg city, 40 mpg highway, 37 mpg combined

Analysts propose several reasons for the plateau in hybrid sales.

First, most hybrids from Asian makers--including the three above--are built in their home countries, even if non-hybrid versions of the same car (e.g. Hyundai Sonata) are built in the U.S.

That means the March 11 earthquake and resulting tsunami, which severely damaged large portions of Japan's industrial infrastructure, cut off or limited the supply of hybrid models for some time. Some makers--Honda in particular--are still suffering from production cutbacks.

2011 Honda Insight

2011 Honda Insight

Hyundai, on the other hand, was unaffected by the earthquake, and its hybrid Sonata is rapidly climbing the sales charts. At current rates, the 2011 Hyundai Sonata Hybrid will pass the 2011 Honda Insight this month to take second place on the sales charts for 2011.

Second, hybrid cars are still more expensive than gasoline cars of the same size. Yes, gasoline costs are lower, but retail buyers chronically underweight running costs and overemphasize purchase price--meaning hybrids carry a disadvantage on first glance.

Third, U.S. buyers can now choose from a far broader range of vehicles with a combined EPA rating of 30 mpg or more.

While the relative value of improvements to gas mileage are confusing to many, a 33-mpg combined rating in a conventional gasoline car may be perceived as "good enough" for many buyers who aren't inclined to go for the top 50-mpg fuel economy of the Prius.

After all, with gas at $3.50 a gallon, the cost difference over 10,000 miles between 33 and 50 mpg is just $350. Even if buyers don't do the math, many likely understand the declining cost savings at the higher end of the mileage scale.

2011 Hyundai Sonata Hybrid

2011 Hyundai Sonata Hybrid

But take heart, hybrid fans. Virtually every carmaker is working on expanding its hybrid offerings, simply because global gas-mileage and carbon emissions standards will require that some portion of future lineups include vastly more fuel efficient vehicles.

All cars will get more efficient, and gasoline cars may close the gap with today's hybrids (e.g. the SkyActiv engine in the 2012 Mazda Mazda2 subcompact may deliver a combined rating of more than 40 mpg on U.S. test cycles).

But there'll be more hybrids available, and their mileage too will increase--even if, like GM with its mild-hybrid Buick eAssist technology, they're not necessarily called "hybrids".

This is just the start of a long evolution in car technology.

Hmmmmmm. What would be the hybrid-car equivalent of a "Darwin fish" symbol?



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