Here are some quick factoids from a NY Times article on car sales and the whether it's economical (overall) to trade in a SUV for a compact car.

 

"Total S.U.V. sales were down 43.3 percent this July from a year ago, according to Autodata, an automotive information services company in Woodcliff Lake, N.J...

 

..Used S.U.V. prices were down 12 percent for the months of May and June, compared with the same period a year earlier, according to J. D. Power and Associates data. But certain models had even sharper declines. For instance, the price of the Ford Excursion was down 27 percent, Hummers fell 25 percent, while Suburbans dropped 24 percent.

 

Take a standard 2005 Ford Explorer in good condition with 50,000 miles on it, for instance. According to Kelley Blue Book, a dealer might give you a stunningly low $6,740 when trading it in now. Selling it to a private party might net you $10,000, if you are lucky. In theory, a dealer would spiff it up and try to sell it for $14,315. But a bargain hunter might be able to find a sales lot full of Explorers coming off a lease and pay many thousands less...

 

...Sales of vehicles with four-cylinder engines represented 47.2 percent of all new vehicle sales during June, up from 38.4 percent of all new sales compared with the year-earlier period. “They would be even higher if they were available,” said Charlie Vogelheim, vice president of automotive development at J. D. Power and Associates.

 

Take the Honda Civic: On average, there was a 16-day supply of these vehicles at the end of June, versus a 32-day supply a year ago (meaning it would take 16 days to sell existing inventory off a dealer’s lot), according to Autodata. There was a nine-day supply for the Toyota Prius, down from a 17-day supply last year. There was a 41-day supply for all new cars in June, down from 49 days last year."

 

In other words demand for certain compact cars has effectively doubled and the % of cars sold with four cylinder engines has increased by 23%.

 

I'll throw in some other anecdotes:

 

A friend of a friend tried to trade in a Chevy Tahoe she paid $50k cash for the year before and was offered $14k for it a $36k hit, and she'd have to come up with another $14k or to get the Accord she wanted.