American Trucking Associations' advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index increased 0.2% in September after falling 4% in August. In September, the index equaled 117.6 (2015=100) compared with 117.3 in August.

"This was the first month in 2019 that we did not see a signficant increase or decrease in tonnage," said ATA Chief Economist Bob Costello. "For the entire third quarter, the index was up 1.2% over the previous quarter and 4.5% from a year earlier, both are nice gains."

It is important to note that ATA's tonnage data is dominated by contract freight, which is performing significantly better than the plunge in spot market freight this year.

August's reading was revised down compared with our September press release.

Compared with September 2018, the SA index increased 3.5%. The index is up 4.1% year-to-date compared with the same period last year.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 114.8 in August, 7.5% below the August level (124). In calculating the index, 100 represents 2015.

Trucking serves as a barometer of the U.S. economy, representing 70.2% of tonnage carried by all modes of domestic freight transportation, including manufactured and retail goods. Trucks hauled 10.77 billion tons of freight in 2017. Motor carriers collected $700.1 billion, or 79.3% 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 5th day of each month. The report includes month-to-month and year-over-year results, relevant economic comparisons, and key financial indicators.