American Trucking Associations' advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index declined 2.6 percent in February after rising 1.6 percent in January. In February, the index equaled 109.2 (2015=100), down from 112.1 in January.

ATA revised the January increase from the originally reported 2.0 percent to 1.6 percent. 

Compared with February 2017, the SA index jumped 5.7 percent, which was below January's 8.4 percent year-over-year gain, but still well above 2017's annual increase. For all of 2017, the index increased 3.8 percent over 2016. Year-to-date, compared with the same two months in 2017, tonnage is up 7.1 percent.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 99.7 in February, which was 6.7 percent below the previous month (106.8).

"Despite a softer February than January, freight remains robust as exhibited in the year-over-year increase," said ATA Chief Economist Bob Costello. "The drivers of truck freight – personal consumption, factory output and construction – are good, plus the inventory cycle is in favor of motor carriers, so I expect freight tonnage to grow at a decent pace in the months ahead."

Trucking serves as a barometer of the U.S. economy, representing 70.6 pecent of tonnage carried by all modes of domestic freight transportation, including manufactured and retail goods. Trucks hauled nearly 10.5 billion tons of freight in 2016. Motor carriers collected $676.2 billion, or 79.8 percent of total revenue earned by all transport modes.

ATA calculates the tonnage index based on surveys from its membership and has been doing so since the 1970s. This is a preliminary figure and subject to change in the final report issued around the 10th day of the month. The report includes month-to-month and year-over-year results, relevant economic comparisons and key financial indicators.