The American Trucking Associations' advance seasonally adjusted For-Hire Truck Tonnage Index increased for the sixth time in the last seven months, gaining another 0.9 percent in April. This followed a 0.4 percent increase in March.

This puts the index at 110.2 (2000=100), the highest level since September 2008. Over the last seven months, the tonnage index grew a total of 6.5 percent.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 111.3 in April, down 4.4 percent from the previous month.

Compared with April 2009, SA tonnage surged 9.4 percent, which was the fifth consecutive year-over-year gain and the largest increase since January 2005. Year-to-date, tonnage is up 6 percent compared with the same period in 2009.

ATA Chief Economist Bob Costello said the latest tonnage reading fits with a sustained economic recovery. "Truck tonnage volumes continue to improve at a solid, yet sustainable, rate. Tonnage is being boosted by robust manufacturing output and stronger retail sales."

Costello also reiterated a statement from last month's release, saying: "For most fleets, freight volumes feel better than reported tonnage because the supply situation, particularly in the truckload sector, is turning quickly."