It happens every time gas prices spike, and it's happening again: Small-car sales are soaring.

In fact, the total of 2.1 million compact and subcompact cars sold over the nine-month period ending in September is up by fully 50 percent compared to the same period a year ago.

That's the highest market share for small cars since 1993.

There's also some "bracket creep" at work: Today's subcompact is as large on the outside as the compacts of 10 or 15 years ago.

It's all due to new, far more stringent safety standards, which require thicker pillars, stronger roofs, and more complex front-crush structures.

They're all required to let the newest models score as well on tougher crash tests as their predecessors did, but they all take up more space and expand a new car's length and width.

So while the EPA continues to define car classes by interior volume (compacts have 100 to 110 cubic feet, subcompacts 85 to 100 cubic feet, and minicars less than that), the footprint of the vehicles containing that volume has grown steadily.

The sales of subcompacts and even minicars are also helped by some new models that have arrived on the market in the past 18 months.

The 2013 Dodge Dart compact sedan, Chrysler's first high-volume small-car entry in many years, is finally making its way into dealerships.

The company is still ramping up production, but sales are growing steadily amid signs that the Dart may finally give Chrysler the volume compact car it's needed since the demise of the Dodge Neon.

Remarkably, even the Fiat 500 minicar is marking stellar sales: More than 4,000 of the little three-door hatchbacks were delivered in September.

In compacts--a much larger segment than subcompacts--the 2012 Honda Civic sedan and coupe were all-new this year, as was the Toyota Yaris.

2012 Chevrolet Sonic, road test, Catskills Mountains, October 2011

2012 Chevrolet Sonic, road test, Catskills Mountains, October 2011

Ford sold more small cars last month than it has for a decade during the month of September, and General Motors especially benefited from its new small-car entries.

The 2012 Chevrolet Sonic subcompact launched last year is a vast improvement on its Chevy Aveo predecessor. Chevy's new Spark minicar--despite not getting much better gas mileage than the larger, more comfortable Sonic--hit the market just as gas prices rose sharply.

At a Chevrolet press event yesterday, GM's volume-car brand said deliveries of the Sonic and Spark, along with the Cruze compact sedan, have been strong--contributing to an 11-percent overall rise for sales through September.

Helped by its small-car entries, "we're seeing is a 63 percent increase in people saying, 'I would definitely consider a Chevrolet,'" Chevrolet's director of small-car marketing, Christi Landy, told The Detroit News.

2013 Chevrolet Spark minicar, New York City, Aug 2012

2013 Chevrolet Spark minicar, New York City, Aug 2012

Will small-car sales continue?

The soaring sales may well show an entirely new generation of buyers that smaller vehicles can be as comfortable, feature-laden, and stylish as the larger cars whose market share is falling.

But, as usual, it will likely all depend on gas prices.


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