Now that the 2010 Toyota Prius is available at most Toyota dealers, at least for test drives, we're waiting for its half-brother--the 2010 Lexus HS250h--to appear at Lexus stores around Labor Day.

We've wondered for awhile what kind of sales Lexus expected, and now Automotive News reports that the sales goal is about 25,000 units for its first full year.   For perspective, that's roughly 14 percent of the sales goal of 180,000 Priuses over the same period.

In 2008, Lexus sold 260,000 cars and light trucks, or 12 percent of Toyota's sales of 2.2 million vehicles. Netting out light trucks, the figures for cars alone are 150,000 and 1.2 million, respectively, with Lexus selling 13 percent as many cars as Toyota.

So the HS falls roughly in line with the overall ratio of Lexus-to-Toyota vehicle sales. Perhaps not suprising, but the HS is a bit of a gamble for Lexus.

The HS is the first dedicated Lexus hyrid model; there is no gasoline-only version of the car, which shares many of its underpinnings with the much higher volume 2010 Prius.

When Lexus launched the HS250h at the Detroit auto show in January, it noted that more than half of all luxury buyers have considered a hybrid.

On the other hand, the Prius itself has become a substitute for luxury vehicles that no other fuel-efficient car competes with, begging the question of whether the two cars will compete directly against each other.

Our colleague Bengt Halvorson has driven the 2010 Lexus HS250h, and reports that while its mileage was considerably below the 2010 Prius combined rating of 50 miles per gallon, it's simply a much nicer car.

And it still returns EPA ratings of 35 mpg city / 34 mpg highway, though Bengt found his mileage varied considerably with driving style.

Thus far, Lexus has not released pricing for the HS.

In a comment to our post on the challenge of pricing the 2010 Lexus HS250h, one reader reported a dealer comment that it would top out around $40,000. Stay tuned.

2009 Detroit auto show

2009 Detroit auto show

[Automotive News, subscription required]