Net income more than doubled for LTL carrier Old Dominion Freight Line (ODFL) in the second quarter of this year, driven by a double-digit increase in tonnage. The carrier said its net income reached $21.5 million on 16.5% higher revenues of $368.3 million, compared to earnings of $10.7 million on revenues of $316.2 million in the second quarter last year.

For the first half of 2010, net income climbed to $29.2 million on a 12.2% increase in revenue to $686 million, compared to earnings of $14.7 million on revenues of $611.3 million during the same period in 2009.

“The 16.5% increase in our second-quarter revenue was driven by a 13.4% increase in tonnage, the first double-digit tonnage increase we have achieved in two years,” said David Congdon, ODFL president & CEO. “This increase in tonnage was the result of a 6.9% increase in shipments and a 6% increase in weight per shipment.”

He also noted that ODFL’s revenue per hundredweight increased 3% for the second quarter, although this metric benefited from higher fuel surcharges. After excluding fuel surcharges, revenue per hundredweight declined 1.1%, Congdon said, primarily due to the negative effect on pricing from the increase in weight per shipment.

“Although we are seeing considerable strength in revenue and tonnage thus far in July, our outlook remains somewhat cautious for the second half of 2010,” he cautioned. “We remain uncertain about the strength and sustainability of the economic recovery as well as the potential impact from regulatory changes affecting, among other issues, healthcare, energy, labor and taxes.”