August trucking activity rebounded in California as hauling cargo to Los Angeles and Long Beach ports picked up, and air freight movement in San Diego International Airport showed improvement, according an economic index released last week.

The Ceridian-UCLA Pulse of Commerce Index is a measure of the flow of goods to U.S. factories, retailers and consumers. It measures diesel fuel purchases at 7,000 truck stops nationwide.

Meanwhile, the index for all trucking activity in the United States fell for its third consecutive month.

“We just think there is no locomotive to pull us out,” Ed Learner, director of the UCLA Anderson Forecast, told the North County Times. “California got into this mess earlier and seems like it is healthier than the rest of the nation.”

The only driver of the improved California trucking activity is exports, he said.

The index for California alone — broken out from the broader Pacific Coast index — rose to 103.27 in August, up 2.52 from 100.75 in July. Nationally, the index fell 1.31 points to 94.61 in August from July’s 95.92. The August figure is slightly below the level seen in December 2010. The index improved somewhat earlier this year, but has dropped since March, which was the highest level of trucking activity since the index’s 95.59 in July 2008.

Leamer said that he remains concerned about shrinkage of the manufacturing and construction sectors, a frugal consumer who shows no signs of spending more on goods and services, and high oil prices. Unemployment also remains high.

Also a worry, Leamer said, is a growing trend to higher diesel fuel prices that have risen again after sliding this summer. According to AAA’s Daily Fuel Gauge Report, the U.S. average for diesel was $3.909/gal. last week, versus $3.902 a month ago and $2.955 a year ago.

Leamer believes that fears of a double-dip recession are exaggerated, but he forecasts economic growth at less than 3% in 2011.