These are the best of times for the recovering auto industry — many big carmakers experienced impressive double-digit growth. At this rate, General Motors says, we’re in for a 14 to 14.5-million auto sales year in the U.S., and that ain’t too shabby, considering 2010 was 11.5 million and the dismal 2009 10.4 million.


So why aren’t people celebrating? The short answer is that even larger numbers were expected, and nobody knows where we’re heading. It’s also far from clear whether the big investments in green technology will pay off in the short or long term.


One month subcompacts, hybrids and electrics look like a winner, and the next month they plunge. The big drivers are gas prices, which are staying high but moderating a bit, and the uncertain state of the economy, which is putting some sales on hold. Separate consumer confidence surveys — one showing people buying again because of more affordable gas, the other showing them holding back because troubling economic indicators — illustrate the warring impulses.


My advice to the pundits is to avoid making big pronouncements about what will happen with electric vehicles. If the early adopters like their cars, the word of mouth will spread, and the modestly rolling stone will gather momentum. If problems dominate, as they have with some marques (especially Fisker), then the pace could stagnate. Then again, cheaper, better batteries are reportedly just around the corner, and that could change the whole equation.


May was a relatively fair-weather month, with some storm clouds passing over. Compared to a year ago, Toyota (the biggest winner) was up 87 percent. That’s mainly the result of its dealers finally having full showrooms, following the Japanese tsunami and earthquake. The Prius remains a big winner for the company, with an incredible 21,477 sold last month.


The hatch remains the most popular model, accounting for more than half of the sales, but the results for the other family members justifies the decision to diversify: Prius C, 3,693; Prius V, 3,645; Prius Plug-In, 1,086. The new pint-sized C (at right) is doing well because of its stellar fuel economy and low price, despite its getting slammed by Consumer Reports (mainly for a chintzy interior). Here's what CR said on video:



Chrysler, which surely deserves a Comeback Kid title, was up 30 percent, reflecting glory on Fiat CEO Sergio Marchionne and reflecting a mostly new and revitalized product line. If they could just move more of those Fiat 500s, everybody would be happy. The announcement that Fiat will be teaming up with Alfa-Romeo to produce a Miata-based sports car was quite welcome. It’s just the car to bring back the brand that’s been gone so long that most Americans say, “Alfa what?”


VW is up 28 percent, with Americans embracing the new Beetle and the American-made Passat. It was a good month for the German automakers generally. Mercedes Benz had its best U.S. May ever, shipping 22,515 cars. Add in Smart and Sprinter, and it's 25,259 vehicles. The C, E and M-Class were all in demand. And the upscale SLK roadster was up an incredible 1,855.3 percent — it's high times for Greenwich, Conn.'s hedge fund traders.


Nissan is also lookin’ good, up 21 percent. Nissan sold 510 Nissan Leafs in May, which deserves inclusion on the New York Times Magazine’s “meh” index. The numbers are up from 370 in April, but no match for last March’s 1,142 (the record so far). 


General Motors had mixed news to report. Sales were up 2.4 percent overall compared to May of 2011, but the bestselling Cruze dropped 20.3 percent, to 19,613. It’s not the fastest-selling car in its segment anymore, because the Japanese are back to reclaim the title. But the Volt is selling fairly well, with 1,680 moved in May. It’s not an exaggeration to say that the Volt is the bestselling electrified car in history, though Carlos Ghosn is fond of pointing out that the Leaf holds that title for battery cars.


Ford’s results are instructive, and again quite mixed. The company was up a so-so 3.9 percent in May. It’s biggest news is the hot selling pace of the new-for-2010 Focus compact, which has sold an impressive 110,000 units this year. Sales of the Focus are up an amazing 43.8 percent from 2011. But the subcompact Fiesta (left), all new in 2011, isn’t doing nearly as well; its 2012 sales are down 27 percent from last year. In May, Ford sold 24,000 Focuses and 6,000 Fiestas — that’s an 80/20 split.


The same basic trend is visible at GM, which has a 27/73 split between the Sonic subcompact and the Cruze compact. There’s a none-too-surprising lesson here: Americans today will buy the biggest car they can find — as long as it gets good fuel economy. Detroit is bending over backwards to bring 30 highway mpg to cars like the Chrysler 300. In the Cruze, you can even get 40 mpg if you opt for the Eco model I enjoyed driving last week.


Hey, people aren’t crazy. The problem with tiny cars like the Smart, Scion iQ and, yes, the Fiesta/Sonic, is that the modest fuel economy gains and price advantage aren’t enough to offset the loss in storage and creature comforts. We’re Americans, we’re big, and we think bigger. Super-size me has long applied to cars, but now fuel economy — the number one concern for many buyers — is the wild card that has to be taken into account.


Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

The auto industry's cloudy outlook
2012 car sales are looking up, so why isn't the industry happy? Everybody's nervous that the good times won't last, and electrics remain a question mark.