According to the American Trucking Associations, its advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index dropped 0.4% to 113 (2015=100) in June, mirroring the 0.4% increase from May. ATA also revised the May increase from the originally reported 0.7% to 0.4%.

The SA index increased 7.8% over June 2017, an increase from May’s 7.4%, while year-to-date tonnage increased 7.9% when compared with the first half of last year. This jump outperformed the annual gain of 3.8% in 2017.

Comparably, the not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, totaled 116.3 in June – 1.1% less than the previous month of 117.6.

“In the second quarter, we saw the tonnage index jump 1.8% from the previous quarter and 8.4% from a year earlier,” said ATA Chief Economist Bob Costello. “This robust growth fits with what is likely to be a very strong GDP reading for the second quarter. I expect the growth in tonnage to moderate, but remain at very high levels in the months ahead.”

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