The popularity of cars can be measured by several factors. Among these are total unit sales in a year, market share versus direct competitors, and sales improvement year-over-year. The best measure is none of these. Rather, it is the availability of a particular model on any given day, week or month. The auto manufacturing industry calls this measure “days to turn” or “time on lot.” The average car or light truck takes 50 or 60 days to sell once a dealer gets it. Some models can stay on lots for more than 90 days. The vehicles that are in really great demand are on lots for fewer than 20 days, and sometimes closer to 10.

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An analysis of cars that sit on dealer lots for the least time finds that they fall into three groups. The first consists of extremely expensive cars, with sticker prices above $50,000 or even $100,000. The next group is inexpensive sports cars. The third is cars that get very high mileage, including hybrids. Most of the cars and light trucks that have tight inventory have been on the market for several years. The Ford Escape and Subaru Impreza are examples of economy-priced cars that have sold well for five years or more.

The price range of vehicles that are in tight supply is surprisingly wide, and the range of car types is equally broad. The list includes cars that cost less than $25,000 and two that cost more than $100,000, as well as heavy SUVs and light economy cars with small engines.

Based on November 2012 days-to-turn data for vehicles sold in the United States, provided by Edmunds.com, 24/7 Wall St. identified the 10 models that spend the shortest time on the lot. Edmunds also provided annual sales for these models dating back to 2007, as well as the first 11 months of sales for 2012. We also identified base MSRP of these models, as well as additional features from manufacturer websites.

These are 24/7 Wall St.’s “Cars So Hot They Are Out of Stock.”

10. Mercedes-Benz M-Class
> Days to turn: 18 (tied for 9th fewest)
> 2012 sales: 33,860
> Price: $47,270
> Configuration: SUV

Mercedes has four lines of SUVs, including the M-Class, which is priced in the middle of its fleet. Like most vehicles from major manufacturers, the M-Class comes in a number of models. The least expensive is the ML-350, which carries a 3.5-liter engine used in a number of other vehicles in the Mercedes model line. Like most car companies, Mercedes offers the M-Class in several configurations and with several engines. The top-end M is the version made by the AMG high-performance division of Mercedes, which was established in 1967. The ML63 has a base price of $96,100 and comes with a 518-horsepower engine.

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9. Subaru BRZ
> Days to turn: 18 (tied for 9th fewest)
> 2012 sales: 3,647
> Price: $24,495
> Configuration: two-door coupe

The Subaru and its nearly identical twin — the Scion FR-S — were designed and built in a joint venture between Subaru and Toyota Motor Corp. (NYSE: TM). The cars were launched to great acclaim. Recently, each was among the top picks by the car reviewers of The New York Times. One of the evaluations: “The BRZ’s chassis, steering, brakes and manual gearbox are all beyond reproach, and a compact boxer engine helps to keep the car low, balanced and planted on the pavement.” The car is also inexpensive, which means it can appeal to a relatively broad audience. But it is rare among Subarus in not having all-wheel drive.

7. BMW M6
> Days to turn: 17 (tied for 7th fewest)
> 2012 sales: 391
> Price: $106,100
> Configuration: two-door coupe

BMW’s M cars and SUVs are made by its high-performance division. The vehicles are rare and very expensive. A case in point is the M6, the muscle version of BMW’s high-end two-door mid-sized coupe, which has a 560-horsepower engine. BMW markets the car primarily against two other very high-end sports cars — the Mercedes-Benz CL63 and Audi R8 — each of which also has a base price well above $100,000. Potential buyers of the M6 can get additional packages with amenities, including options such as a heated steering wheel for up to $5,300.

7. Ford C-Max Hybrid
> Days to turn: 17 (tied for 7th fewest)
> 2012 sales: 7,596
> Price: $25,200
> Configuration: four-door sedan

The C-Max Hybrid was new for the 2012 model year. It comes with a two-liter electric hybrid engine, which Ford Motor Co. (NYSE: F) claims gets 47 mpg in both city and highway driving. The C-Max is the first plug-in hybrid from Ford in the United States, which puts it into competition with other large international car companies that have released electric cars in the past two or three years. The Chevy Volt probably has gotten the most press of these cars, largely because of flaws with its batteries. As the sales figures for the C-Max, Volt and Nissan Leaf show, it has remained difficult to gain a mainstream consumer base for electric cars.

6. Hyundai Genesis Coupe
> Days to turn: 16
> 2012 sales: 12,469
> Price: $24,250
> Configuration: two-door coupe

The Genesis comes in both coupe and sedan models. The sedan has a much higher base price — $34,200. However, it only takes a more powerful engine and additional features to get the price of the coupe above that. The base model has a two-liter turbo engine that generates 274 horsepower. The more powerful six-cylinder engine puts out 348 horsepower, and fully loaded with all available accessories it is priced above $35,000. Hyundai markets the Genesis Coupe against the Ford Mustang, the Infiniti G Coupe and the Chevy Camaro.

5. Kia Soul
> Days to turn: 15 (tied for 4th fewest)
> 2012 sales: 108,601
> Price: $14,400
> Configuration: SUV

The Soul has posted sharp sales gains every year since 2009. In 2012, well above 100,000 will be sold. The Soul is among the least expensive vehicles Kia sells. It is also one of the cornerstone’s of Kia’s success in the United States. The South Korean stablemate of Hyundai sold 518,421 vehicles in all through the first 11 months of 2012, up 17% from the same period in 2011. The base Soul comes with a tiny 1.6-liter, four-cylinder engine that puts out 138 horsepower. Kia claims the engine gets 25 mpg in city driving and 30 mpg on the highway. For those inclined to splurge, there are several two-liter engine models.

Also Read: The Top Selling Luxury Cars in America

4. Scion FR-S
> Days to turn: 15 (tied for 4th fewest)
> 2012 sales: 9,922
> Price: $25,255
> Configuration: 2-door coupe

This sports car, offered by the low-price Scion brand of Toyota USA, is essentially the same vehicle as the Subaru BRZ. The power plant is a Boxer engine, a widely regarded design used in a number of Subaru cars. In marketing the car, Toyota traces its lineage back to the Sport 800, which was launched in 1967, although it is a stretch to find much in common between the two vehicles. A buyer not terribly concerned about price can drive the sticker of an FR-S well above $28,000 by adding a long-term service package and an $845 BeSpoke Audio System.

3. Mercedes-Benz G-Class
> Days to turn: 14
> 2012 sales: 1,162
> Price: $113,000
> Configuration: SUV

The G-Class is the highest-end line of Mercedes SUVs. That may be why, since 2007, average annual sales have only been about 1,000 units. The G comes in two versions. The first has the 5.5-liter engine used in two other of Mercedes’ more powerful cars that are not part of the race-inspired AMG line. The second is the G63 AMG, which has a base price of $134,300. Its biturbo V8 puts out 536 horsepower to power an SUV that can pull as much as 7,500 pounds. According to a writer for Road & Track, “Mercedes claims the 5721-pound beast hits 60 mph in 5.3 seconds. I believe it.”

2. Ford Shelby GT500
> Days to turn: 11 (tied for the fewest)
> 2012 sales: 4,216
> Price: $54,200
> Configuration: two-door coupe

Carroll Hall Shelby, who died this year, was a race car driver and builder of superpowered engines. The Mustang comes with several engine sizes, starting with a V6. The high-end of the model line, the Shelby GT500, has a 5.8-liter supercharged V8, which puts out 662 horsepower. The car sports Brembo performance brakes and a six-speed manual gearbox. According to Motor Trend, the Ford Shelby GT500 has a mind-boggling 0 to 60 time of 3.5 seconds. As if the car did not have enough performance of its own, Ford offers a $3,495 “Performance Package” with special wheels and springs.

1. Ford Fusion Hybrid
> Days to turn: 11 (tied for the fewest)
> 2012 sales: 10,856
> Price: $27,200
> Configuration: four-door sedan

The Fusion Hybrid has not gained much traction for Ford. Sales reached 20,816 in 2010, but will be about flat from last year at around 12,000. The Fusion is the least-expensive hybrid sold by America’s second-largest car company. Ford claims the car gets 47 mpg for both city and highway driving. The fuel plant used in the Fusion Hybrid is a 2.0L Atkinson-Cycle I-4 Engine, which Ford says can go “from a complete stop and can travel under light to normal acceleration up to 62 miles per hour on electric power alone … with no fuel used.” With a full set of options, the Fusion Hybrid costs as much as $36,000, which seems a small price to pay for a car that saves all that gas.

Douglas A. McIntyre

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