Truck tonnage in 2011 rose 5.9% over 2010, representing the largest annual increase since 1998, according to the American Trucking Associations. Also, tonnage for December 2011 was 10.5% higher than December 2010, the largest year-over-year gain since July 1998. November tonnage was up 6.1% over the same month last year.

The ATA’s advanced seasonally adjusted For-Hire Truck Tonnage Index jumped 6.8% in December after rising 0.3% in November 2011. The latest gain put the SA index at 124.5 (2000=100) in December, up from the November level of 116.6.

“While I’m not surprised that tonnage increased in December, I am surprised at the magnitude of the gain,” says Bob Costello, chief economist with ATA, who points out that it was the largest month-to-month increase since January 2005.

“Not only did truck tonnage increase due to solid manufacturing output in December, but also from some likely inventory restocking,” Costello adds. “Inventories, especially at the retail level, are exceedingly lean, and I suspect that tonnage was higher than expected as the supply chain did some restocking during the month.”

ATA calculates the tonnage index based on surveys from its membership and has been doing so since the 1970s.

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