The American Trucking Associations seasonally adjusted For-Hire Truck Tonnage Index increased 1.7 percent in March after falling a revised 2.7 percent in February.
Compared with March 2010, the seasonally adjusted index was up 6.3 percent, an increase from February's 4.4 percent year-over-year gain, according to the ATA.
For the first quarter, typically a slow period for trucking, the seasonally adjusted index increased 6.1 percent from a year ago and 3.8 percent from the fourth quarter.
The unadjusted index, which reflects raw freight volumes, was up 5.9 percent year-over-year and 20.7 percent from February's unadjusted tonnage figures.
Those monthly and quarterly increases in freight volume occurred despite rising fuel costs in March and often bruising winter storms in January and February.
January was the strongest month so far this year, with a 7.6 percent seasonally adjusted jump in tonnage year-over-year and a 3.5 percent month-to-month gain.
During January and December, truck tonnage jumped a combined 6.1 percent.
The gains in March came despite rising fuel prices that affected consumers and trucking operators alike, said ATA Chief Economist and Vice President Bob Costello.
"While I still think the industry will continue to grow and recover from the weak freight environment, the rapid spike in fuel prices will slow that growth," he said.
Stronger U.S. manufacturing is benefiting trucking, he said.
Durable goods manufacturing in the U.S. increased 9.9 percent in 2010, after decreasing 12.7 percent in 2009, the Bureau of Economic Analysis said Tuesday.