The American Trucking Associations’ advanced seasonally adjusted For-Hire Truck Tonnage Index decreased 4.5% in March, following a 7.2% surge during February. In March, the index equaled 137.6, down from the all-time high recorded in February (144).

Compared with March 2015, the index was up 2.2%, which was down from February’s 8.6% year-over-year gain. Year-to-date, compared with the same period in 2015, tonnage was up 3.9%.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by fleets before any seasonal adjustment, equaled 142.1 in March, which was 10.2% above the previous month (129).

“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 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,” he said. “In addition, freight volumes are softer than the overall economy because of the current inventory overhang throughout the supply chain.”

The decrease is the largest monthly contraction for the index since September 2012 (-5.3%).