The latest drop lowered the seasonally adjusted index from 110 (2000=100) in July to 106.9 in August.
Compared with August 2009, seasonally adjusted tonnage climbed 2.9 percent, which was well below July's 7.4 percent year-over-year gain. Year-to-date, tonnage is up 6.2 percent compared with the same period in 2009.
The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 113.5 in August, up 3.2 percent from the previous month.
ATA Chief Economist Bob Costello said that August's data highlights that the economy, while still growing, is slowing. "We fully anticipate sluggish economic growth for the remainder of this year and the latest tonnage numbers are reflecting that slowdown." However, Costello believes that the trucking environment has changed dramatically. "While I'd much rather see better tonnage figures, motor carriers can now do better with small increases in demand since so much supply left the industry during the recession."