The American Trucking Associations’ advanced seasonally adjusted For-Hire Truck Tonnage Index decreased 4.3% in January, after edging 0.8% lower in December. In January, the index equaled 124.4 (2000=100) versus 130.0 in December. The all-time high was in November 2013 (131.0). Compared with January 2013, the SA index increased 1.2%.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 122.3 in January, which was 0.3% below the previous month (122.7).

ATA recently revised the seasonally adjusted index back five years as part of its annual revision. For all of 2013, tonnage was up 6.3%, slightly better than the 6.2% originally reported. In 2012, the index increased 2.3%.

“Like most economic indicators, truck tonnage was negatively impacted by bad winter weather in January,” said ATA chief economist Bob Costello. “The thing about truck freight is that it’s difficult to catch up. Drivers are governed by hours-of-service regulations and trucks are limited to trailer lengths and total weights, thus it is nearly impossible to recoup the days lost due to bad storms.”

As a result, Costello said January will be a tough month to gauge.

“January wasn’t just one storm, it was several across a large part of the country. Therefore, I wouldn’t panic from the largest monthly drop in two years,” Costello said. “I’ve heard from many fleets that freight was good, in-between storms. The fundamentals for truck freight still look good.”