The American Trucking Associations' (ATA) For-Hire Truck Tonnage Index increased a slight 0.9 percent in March. That's coming after a 0.7 percent decrease in February, the only month in the last five that recorded a drop.

Since November 2012, the index is up 7.6 percent and when compared with March 2012, up a solid 3.8 percent, beating February's 3.1 percent year-over-year gain.

"Fitting with the expectation for solid gross domestic product growth in the first quarter, tonnage was strong in March and the quarter overall," ATA Chief Economist Bob Costello explianed. "At 3.9% year-over-year growth, the first quarter increase was the best since the final quarter 2011.

Costello said to expect freight tonnage to slow in the coming months as the U.S. federal government sequester continues and households finish spending their tax returns.

"The good news for tonnage is housing starts are growing and energy production is good — both of which generates heavy freight. However, these two sectors alone won't be enough to keep the overall index growing at a 3.9 percent clip in the second quarter."