ARLINGTON, VA. — The American Trucking Associations’ (ATA) advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index tapered 0.9 percent in August after July’s 0.4 percent increase.

While the drop in August didn’t erase the combined 1.5 percent gain in June and July, it was still significant, ATA said.

Compared with August 2011, the SA index was 3.2 percent higher. Year-to-date, compared with the same period last year, tonnage was up 3.7 percent.

The not-seasonally adjusted index was 5.7 percent above the previous month.

“While there has been acceleration in housing during the last few months, truck tonnage is being weighed down by a flattening in manufacturing output and an unintentional increase in inventories throughout the supply chain,” explained ATA Chief Economist Bob Costello. “While choppy, tonnage has essentially been flat this year with August being the second lowest month of the year.”