The 3.9% gain in November was revised from a 3.7% increase ATA reported on Dec. 18.
The back-to-back increases in November and December were by far the best of gains of 2012. As a result, the SA index equaled 121.6 (2000=100) in December versus 118.3 in November. Despite the solid monthly increase, compared with December 2011, the SA index was off 2.3%, the worst year-over-year result since November 2009.
For all of 2012, tonnage was up 2.3%. In 2011, the index increased 5.8%.
The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 110.3 in December, which was 4.9% below the previous month.
"December was better than anticipated in light of the very difficult year-over-year comparison," ATA Chief Economist Bob Costello said. In December 2011, the index surged 6.4% from the previous month. Costello anticipates more sluggishness in the index this year, especially early in the year, as the economy continues to face several headwinds.
"As paychecks shrink for all households due to higher taxes, I'm expecting a weak first quarter for tonnage and the broader economy," Costello said. "Since trucks account for the vast majority of deliveries in the retail supply chain, any reduction in consumer spending will have ramifications on truck tonnage levels."