American Trucking Associations’ advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index decreased 5.1% in March after falling 2.3% in February. In March, the index equaled 106.8 (2015=100) compared with 112.5 in February.

“March’s drop comes as somewhat of a surprise,” Bob Costello, chief economist for American Trucking Associations, said. “I certainly heard from many fleets that the end-of-quarter rush was good, but early March was soft. Truck freight volumes were also negatively impacted by supply chain issues from the lack of microchips and other inputs. That said, this surprise to the downside does not change my positive outlook going forward. Household spending power is strong and I believe there is plenty of pent-up demand for consumer spending. Single-family home construction and stronger manufacturing output, even with the supply chain issues, will help support tonnage through this year and beyond.”

February’s gain was revised up to -2.3% from American Trucking Associations’ previous report.

Compared with March 2020, the SA index fell 9.5%, which was preceded by a 3.8% year-over-year decline in February.

During the first quarter, seasonally adjusted tonnage fell 0.4% from the final quarter of 2020 and declined 5% from a year earlier.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by fleets before any seasonal adjustment, equaled 110.6 in March, which was 8.9% above the February level (101.6). In calculating the index, 100 represents 2015. ATA’s For-Hire Truck Tonnage Index is dominated by contract freight as opposed to spot market freight.

Trucking serves as a barometer of the U.S. economy, representing 72.5% of tonnage carried by all modes of domestic freight transportation, including manufactured and retail goods. Trucks hauled 11.84 billion tons of freight in 2019. Motor carriers collected $791.7 billion, or 80.4%, of total revenue earned by all transport modes.

American Trucking Associations 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 fifth day of each month. The report includes month-to-month and year-over-year results, relevant economic comparisons and financial indicators.