The American Trucking Associations has reported that its advanced seasonally adjusted For-Hire Truck Tonnage Index increased 3.3% in all of 2019 – about half the annual rise it saw in 2018 (6.7%).

The 2019 performance marks the 10th straight annual increase and, according to ATA, reflects the “very choppy” freight market that motor carriers experienced last year.

The advanced SA For-Hire Truck Tonnage Index climbed 4% in December after falling 3.4% in November. In December, the index equaled 118.2 (2015=100), compared with 113.6 the month before.

“Last year was not a terrible year for for-hire truck tonnage, and despite the increase at the end of the year, 2019 was very uneven for the industry,” ATA Chief Economist Bob Costello remarked in a news release.

“The overall annual gain masks the very choppy freight environment throughout the year, which made the market feel worse for many fleets,” he added. “In December, strong housing starts helped advance the index forward.”

November’s reading was revised down slightly compared with ATA’s December press release. And compared with December 2018, the SA index increased 3%, which was preceded by a 2% year-over-year drop in November. ATA stated that “it is important to note that ATA’s tonnage data is dominated by contract freight.”

On the other hand, the not seasonally adjusted index – which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment – equaled 112.7 in December, or 2% below the November level (115.1). In calculating the index, 100 represents 2015.

ATA calculates the tonnage index based on surveys from its membership. This is a preliminary figure and subject to change in the final report, according to ATA, which is 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.