Automakers are tantalizing the market with 40-mpg small cars and 30-mpg sporty cars. Electric cars from major automakers are due by year's end. Plug-in gas-electric hybrids are under development.

But guess what? The full-size SUV market segment � the bane of mileage-minders � is where the action is.

The jump in sales of full-size SUVs the first half of the year outperformed the rise in the overall auto market, according to tally master Autodata. And the growth rate also outpaced that of small cars, which conventional wisdom says should be the darlings now because of their lower prices and higher mileage.

To be sure, small cars still vastly outsell big SUVs � 974,000 to 121,000 the first six months, Autodata reports.

But their sales were up 14% in the first half compared with the same period a year ago, while the overall market was up 17% and SUVs beat them both with 19%.

"Subcompacts and small cars aren't the hot segments anymore. Gasoline prices have come out of the sky, and we're moving back to something a little more normal" in fuel prices and buyer behavior, says George Magliano, director of North America auto forecasting for consultant IHS Global Insight.

The unexpected SUV surge comes as the government is pressing hard for ever-better mileage that car companies say is only possible with smaller vehicles and smaller engines in big vehicles.

"The American consumer tends not to like small cars, despite what the government would like, and despite how much the manufacturers have committed to small cars," Magliano says.

If the big-SUV sizzle becomes full-fledged sales fireworks, it threatens to catch some companies flat-footed, with too little production capacity for big SUVs, which tend to be high-profit vehicles.

And it could mean big profits for the companies that didn't abandon or drastically cut back their full-size SUV production during the recession.

The traditional, truck-based big SUVs such as Chevy Tahoe and Toyota (TM) Sequoia, are a "license to print cash" because they share so much hardware with full-size pickups, notes auto-industry expert Jim Hall at 2953 Analytics.

The full-size SUV category includes not only traditional truck-style SUVs, but also car-based crossover SUVs such as Ford Motor's (F) Ford Flex and Lincoln MKT and the General Motors' trio of big crossovers sold by Chevy, GMC and Buick.

Good news for autoworkers

The SUV boomlet means real dollars to real workers. General Motors, for instance, has triggered overtime, going to two shifts of five, 10-hour days a week at its Arlington, Texas, truck factory that builds the Chevy Tahoe and Suburban and the Cadillac Escalade.

On top of that, workers have gotten some Saturday overtime lately.

Normal at Arlington is two shifts, each working four 10-hour days a week at straight-time pay; no Saturdays.

Toyota, too, has boosted Sequoia production but wouldn't specify how much.

Infiniti, Nissan's luxury unit, took the rare step of boosting production of a lame-duck model, the 2010 Infiniti QX56 full-size SUV, so dealers wouldn't run out before the redesigned 2011 arrived in July, according to spokesman Kyle Bazemore. "The past few months, the (2010) was selling like crazy," he says, even though sales incentives were about flat.

"There's definitely a buyer for this type of" vehicle, he says. And that might be a bellwether: The QX56 is the biggest and heaviest full-size SUV, excluding lower-volume long-wheelbase models such as Chevy Suburban.

One reason at least some people are looking hard at the big rigs now takes into consideration the fact that the latest fuel-economy regulations will make it tough to keep selling big SUVs or crossovers.

"I wanted to get one before they stop making them. I'm serious," says Steve Schmidt, a small-business owner in Covington, La., who just replaced his 2004 Chevy Tahoe with 130,000 miles on it with a 2010 Tahoe. He uses the SUV both as a family vehicle and for "running around, hauling things" for business.

He says he tows a trailer, too, so he wants a traditional, truck-based SUV. Crossovers typically tow about half as much weight as a truck-style SUV.

He was surprised to find that big SUVs have gotten popular enough again that "selection isn't where it used to be, and incentives aren't where I thought they'd be."

The auto industry historically has overreacted when sales rise by overproducing � then has had to heavily discount to try to keep sales volumes high. They couldn't do that now if they wanted to.

"Manufacturers have taken out some capacity in the reorganizations," so they can't simply crank up the assembly lines, notes Thomas King, senior director at J.D. Power and Associates consultants.

What's behind the sale trend

Driving the big-SUV sales jump:

�Stable fuel prices. Not low, but hovering lately around a U.S. average of $2.75 a gallon for regular gasoline. That's well off the $4.11 record nationwide average set July 17, 2008, after hurricanes halted much of the oil production and shipping in the Gulf of Mexico.

�Improving economic conditions. The economy is still sputtering. And if your job is iffy, or gone, you'll surely ask, "What recovery?"

But it's easier now to get auto loans, which is how nearly all new cars and trucks are purchased.

And because big SUVs tend to be expensive � $40,000 and up for the most part � their sales growth "is kind of a good sign" that people who have money to spend are coming back into the market, notes GM spokesman Tom Wilkinson.

"Better customers, who buy more expensive vehicles," King says.

Studies suggest that roughly the wealthiest one-third of Americans buy about two-thirds of all new vehicles. If that group is back in play, the industry could have an easier time making money this year.

�Pent-up demand. The auto industry uses this so often to explain so much that it's a clich�. But vehicles do wear out.

Many people hung onto their old SUVs through the recession, either due to their personal economic insecurity or because they were uncomfortable bringing home a flashy new vehicle.

"What happened was, people put off buying. They put the money into the 401(k), or simply didn't think it would look right" driving a spanking new, full-size SUV at a time friends and neighbors might be looking for work, Hall says.

But now, their old vehicle is needing more repairs and more frequent maintenance and, like Schmidt, they think it might be time to replace it.

�More reasonable choices. More big SUVs are crossovers than just a year or two ago, making a full-size SUV seem more rational to some buyers.

Crossovers (such as Chevy Traverse and Ford Flex) are based on car chassis, not the body-on-frame construction of truck-based SUVs such as Tahoe or the Ford Expedition.

That makes them lighter � sometimes by 1,000 pounds � than truck-style SUVs. That lets them get by just fine on smaller, less thirsty engines. Their car-like design also typically rides more smoothly and handles better than truck-based vehicles.

They still seat seven or eight people and tote cubic yards of goods; they just can't tow horse trailers or big boat rigs.

Even the big crossover SUVs could slam to a stop, though, if fuel prices rocket � which could happen as the worldwide economy improves and drives up demand for petroleum products.

"There's a point for anyone � if gas goes to $4 or $5 a gallon, we'd rethink" a big SUV, says SUV shopper Matt Hammons, of Keller, Texas. "At $10, we'd move to a city that had good mass transit."

Hammons had been thinking about a Ford Expedition but decided to quit the market. "No change in our financial situation; it was more a thinking-out whether this was the time to buy," he says.

Fuel-economy rules an issue

For automakers, "The real issue is the new CAFE," says Hall, referring to the federal Corporate Average Fuel Economy rules that requires the industry to average � over all vehicles � 35.5 miles per gallon.

It would be hard for big SUVs to come close to their own targets, even though those would be lower than the 35.5 overall average. The truck-style models hit 15 or 16 mpg in combined driving now. The crossovers are just 2 or 3 mpg better.

Automakers are telegraphing their intentions to use smaller gas engines, diesel engines and perhaps gas-electric hybrids in the bigger SUVs to boost their mileage ratings.

If such changes for the sake of CAFE wind up subtracting space and power and adding price � as Hall and others expect will happen � that could diminish big SUVs' attractiveness to some buyers.

"The market is fickle and can change its mind faster than any car manufacturer can respond," Hall says.

As J.D. Power's King more dryly puts it, "We don't see the (full-size SUV sales) reversing to historical levels."