North American freight volume and expenditures rose again in March as shipments picked up significantly from the West Coast ports, according to the latest readings of the Cass Freight Index.

The shipments reading increased to 1.086 for the month, its highest level since November. The measure for expenditures rose to 2.459, its best performance since December.

This happened as the U.S. and global economies did not grow as much as expected in the first quarter, but freight movement in the U.S. continues to strengthen.

The number of shipments inched up 0.3% in March, but is 5.1% lower than the same time a year ago.

According to Rosalyn Wilson, supply chain expert, and senior business analyst with the management services firm Parsons, who provides analysis for the report, railroad shipments increased 4.2% for carload traffic and 12.6% for intermodal, after falling in February. Truck shipments were down in February, the latest month data is available, largely due to bad weather in most of the country. However, the DAT Solutions spot market freight volume indexes, rose 34% in March compared to February.

Freight expenditures rose another 1% in March, following a 4.3% increase in February. However, March payments are 3.5% lower than they were in the same month last year, but 2014 experienced a banner month by comparison, according to Wilson.

“First quarter freight volumes were affected by labor problems, slowdowns and work stoppages at West Coast ports; extreme winter weather throughout much of the country; and a slowdown in the global economy,” said Wilson. “The ports are now dealing with fallout from the labor issues, both good and bad. The Port of Portland in Oregon had two of its biggest container carriers, HanJin and Hapag-Lloyd, drop the port because of slow and unpredictable service stemming from protracted union labor issues. Other ports around the U.S. have been reporting higher container shipments as carriers try other options.”

She said after a rough few months, freight volumes overall were building strongly toward the end of the quarter, and with that growth, rate increases may be seen that could outpace the growth in freight volume.

The Cass Freight Index measures trends in North American shipping activity based on $26 billion in paid freight expenses in all freight modes for Cass Information Systems' customer base of hundreds of large shippers.