ARLINGTON, Va. — American Trucking Associations’ advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index rose 1.2% in March after increasing 1.8% in February.

In March, the index equaled 120.4, compared with 119 in February, ATA said.

“March was the storm before the calm, especially for carriers hauling consumer staples, which experienced strong freight levels,” said ATA chief economist Bob Costello.

But he said there was a huge divergence among freight types. While freight to grocery stores and big box retailers was strong in March, freight was anemic in other supply chains.

“Because of this, and the continued shuttering of many parts of the economy, I would expect April tonnage to be very soft,” he said.

Compared with March 2019, the SA index increased 4.3%, which was preceded by a 2.6% year-over-year gain in February, ATA said.

During the first quarter, the index rose 1.5% compared with the fourth quarter of last year and 2.4% from a year earlier.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 120.9 in March, 11.8% above the February level (108.2).

Trucking serves as a barometer of the U.S. economy, representing 71% of tonnage carried by all modes of domestic freight transportation, including manufactured and retail goods.

Trucks hauled 11.5 billion tons of freight in 2018.