In Miami, the wait for a Mini Cooper can be weeks.

At East Coast Toyota in Wood Ridge, N.J., tiny Scion cars are sold even before they are unloaded from the carrier.

Theres a six-week waiting list for the Scion tC, said John Dee, sales manager at the Toyota store, one of the largest in the Northeast.

And in many U.S. showrooms, the Pontiac Solstice, Chevrolet HHR, BMW 6 series and Ford Fusion run in short supply.

But for every hot seller, theres a lonely car in the back of the lot that has been waiting a long time to find an owner.

How quickly a shiny car or truck sells, or how long it languishes on a dealer lot, has become an important measuring stick as automakers battle to manage inventory levels, maximize factory output and keep a lid on discounts.

Consumers can choose from over 300 car and truck models, and with product development cycles shrinking to 18 to 24 months, the rate at which a new vehicle sells has become a monitor of a models appeal and staying power. Fast sellers are good news not only for automakers but also for dealers, whose finance and insurance charges increase the longer a vehicle goes unsold.

The average car or truck is selling in 58 days this year, up from 54 days in the fourth quarter, but down from 66 days a year ago.

Asian and European nameplates dominate the list of quick sellers, while Kia, Isuzu and a bevy of domestic cars and ? trucks are among the laggards.

The hottest sellers are the redesigned Lexus IS sedan, Toyota Prius and the Scion tC. They all are spending fewer than 15 days on dealer lots before being sold, according to national sales activity tracked through the first eight weeks of 2006 by J.D. Power and Associates Power Information Network.

At the other end of the spectrum are the sporty Chrysler Crossfire, Mitsubishi Endeavor SUV and Hyundai Santa Fe, along with many discontinued models such as the Buick Park Avenue, Ford Thunderbird, Pontiac Grand Am and Lincoln Aviator.

Many new or redesigned models tend to sell fast as automakers ramp up production to fill the pipeline and launch ad campaigns. And luxury models that are sold in limited supplies often dominate the list of fast sellers.

Scion scores big

But some models that have been on the market for a while are showing incredible staying power. Since Toyota launched the Scion youth brand in 2003, the brands funky, affordable models have been practically flying off dealer lots.

There are common themes for models that do very well  they are either redesigned like the Lexus IS or they are sort of unique vehicles like the Prius or (Chevrolet) HHR, said Tom Libby, senior analyst at the Power Information Network.

For slow sellers, price is often a factor. In the case of the Crossfire, many consumers arent willing to plunk down more than $30,000 for a domestic car, said Mike Chung, an analyst with Edmunds.com, a car buyers research Web site.

And the luxury sports car segment, where design and styling change with the weather, is notoriously fickle.

The pricing has a lot to do with it, and thats some of the problem with Chrysler vehicles in general. (The Crossfire) doesnt fall into the luxury segment nor does it fall into the entry level, Chung said. One of the appealing things about the Mustang, for example, is youre getting a good vehicle for a good price.

Price is part of what helped Mini Cooper snag one of its newest owners, J. Todd Bennett, 33, who lives in Miami.

Ive been a huge fan for a long time. Their advertising is phenomenal. It just makes you want to be Mini driver, said Bennett, a managing director for a Web development agency. Hes awaiting the delivery this month of a convertible version in the British racing green hue he wanted.

I like the fact that it still has its heritage in England, and its a BMW underneath at the cost of $24,000. Where else could I get a BMW for $24,000?

The Mini Cooper has maintained a healthy sales pace throughout last year and so far in 2006, taking 23 days to sell on average.

In addition to the fickleness of consumers, the time of year can affect sales.

The redesigned Ford Mustang is a bona fide hit, but it takes longer to sell over the winter, suggesting its appeal seems to grow when warmer weather hits.

Fuel efficiency and bold new designs are other factors that push sales. Full-size SUVs such as the Ford Expedition and Chevrolet Suburban, among the hottest vehicles on the market a few years ago, now take 94 days to sell on average. At the same time, gas-thrifty models such as the Toyota Matrix, Nissan Sentra and Pontiac Vibe are selling twice as fast today as a year ago.

Grabbing attention

The third-row seating offered in the new Jeep Commander is what caught Harold Martins attention. Last week, the 42-year-old Chesterfield resident was getting financing information at Northland Chrysler-Jeep in Detroit for his wife, who wants to trade in her 2003 Jeep Liberty.

Introduced last fall, the typical Commander sells after 48 days better than the industry average.

But yesterdays hit can become todays dud. The Dodge Magnum station wagon, introduced two years ago with much fanfare, now takes an average 192 days to sell.

Older models such as the full-size Chevrolet Blazer, Lincoln Aviator and Suzuki XL-7 SUVs also have sputtered.

Most of these vehicles are due for a refresh, Chung said.

Clearly, the strength and reputation of automotive brands come into play, which explains why many Toyota products fared better than the industrys average and why models from Toyota, Scion and Lexus dominate the top slots. The Toyota brand speaks for itself, said New Jersey sales manager Dee.

Phil Reed, a columnist for Edmunds.com, agrees.

There are certain carmakers that have a built-in advantage like Toyota, Reed said. The reputation is strong.

In comparison, despite strides in quality improvements and much buzz over Hyundais Sonata sedan, Hyundas brand image still struggles. It takes an average 77 days for the new Sonata to sell.

Looking at Hyundai and Kia in particular, its really hurting them, Chung said.