U.S. auto sales in September accelerated to the fastest pace since the federal government’s “cash for clunkers” incentive program last year as deliveries by the top 14 automakers all rose, Bloomberg reported.

U.S. auto sales in September rose to a seasonally adjusted annual rate of 11.8 million, compared with 9.4 million a year earlier, according to researcher Autodata Corp., based in Woodcliff Lake, New Jersey. In August 2009, the pace was 14.2 million, aided by the federal subsidy for fuel-efficient models.

The month’s stronger sales, bolstered by Ford Motor Co.’s 41 percent gain, are a sign that the car market and the broader economy may have bottomed out and that a slow, stable recovery is under way, said Jesse Toprak, vice president of industry trends for Santa Monica, California-based TrueCar.com.

“It’s slightly better than expected, but it’s still a stable and painful growth process,” Toprak said in an interview. “This is another step in a healthy but rather slow recovery. This month, there were no outside forces at play, like government programs or crazy incentives, just the marketplace trying to recover on its own.”

Deliveries at General Motors Co., the largest U.S. automaker, climbed 11 percent from a year earlier to 173,155, the Detroit-based company said today in a statement. Dearborn, Michigan-based Ford, the second-largest, reported 160,873 sales, including more than doubling of deliveries of the Edge sport- utility vehicle and Transit Connect van.

Industrywide deliveries in September were expected to reach an 11.7 million rate, the average of nine analysts’ estimates compiled by Bloomberg. Deliveries in all 2009 were 10.4 million, the lowest since 1982.

The stronger month doesn’t indicate renewed acceleration in economic growth, just that the economy has avoided a double-dip recession, said John Canally, an economist and investment strategist at Boston-based LPL Financial Corp., which oversees $276.9 billion in assets.

“We probably have put a floor under vehicle sales, but the sparks you need to reaccelerate aren’t quite there yet,” Canally said in an interview. “You don’t have robust job growth or robust income growth. Your traditional catalysts for strong consumer spending just aren’t in place yet.”

GM’s deliveries trailed three analysts’ average estimate for a 13 percent gain. Chevrolet brand sales rose 18 percent to 121,479, helped by the Silverado pickup and Equinox SUV. Buick deliveries gained 36 percent to 12,875, aided by the LaCrosse sedan. GMC increased 42 percent to 25,995, and Cadillac rose 11 percent to 12,620.