The American Trucking Associations said Sept. 25 that its seasonally adjusted For-Hire Truck Tonnage Index increased 2.1 percent in August, matching July's increase of the same magnitude. The latest gain raised the seasonally adjusted index to 104.1 (2000=100), which is the index's best reading since February 2009, the ATA said.

The so-called not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 105.8 in August, down 0.5 percent from July.

Compared with August 2008, seasonally adjusted tonnage fell 7.5 percent, which was the best year-over-year showing since November 2008. The ATA defines a "seasonally adjusted" number as one that correlates with historical seasonal activity. For example, October tonnage data would be adjusted to account for the normal uptick in traffic that occurs at the start of the holiday shipping season.

ATA Chief Economist Bob Costello said the latest increase was another positive sign for the industry. "The gains in tonnage during July and August reflect a growing economy and less of an overhang in inventories," Costello said in a statement.

Costello added, however, that the pace of increase will likely moderate from the cumulative 4.3 percent gain over the last two months. "While I am optimistic that the worst is behind us, most economic indicators, including industrial output and household spending, suggest freight tonnage will exhibit moderate, and probably inconsistent, growth in the months ahead," he said.