After a surge in February, the American Trucking Associations' For-Hire Truck Tonnage Index decreased in March, taking away about half of the gains made the month before.

The Truck Tonnage Index decreased 4.5% for the month, equaling 137.6 and down from the reading of 144 in February. February’s number was an all-time high reading.

Even with a loss for the month, the seasonally adjusted index was up 2.2% from March 2015 and is up 3.9% year-to-date.

“As expected, tonnage came back to earth in March from the jump in February,” said Bob Costello, ATA chief economist. “These things tend to correct, and March took back more than half of the surprisingly large gain in February.”

The not seasonally adjusted index, which represents the change in tonnage actually hauled by fleets before seasonal adjustment, equaled 142.1 in March. That was 10.2% higher than February.

“The freight economy continues to be mixed, with housing and consumer spending generally giving support to tonnage, while new fracking activity and factory output being drags,” said Costello. “In addition, freight volumes are softer than the overall economy because of the current inventory overhang throughout the supply chain.”