ARLINGTON, Va. — The American Trucking Associations’ advanced seasonally adjusted For-Hire Truck Tonnage Index jumped 0.5 percent in May.

It was the first increase on a month-to-month basis since January of this year. April’s tonnage reading fell a revised 0.6 percent instead of the previously reported 1.1 percent drop.

The seasonally adjusted index was 3.3 percent higher compared with May 2007, marking the seventh consecutive year-over-year increase. In April, the year-over-year gain was 2.2 percent.

ATA Chief Economist Bob Costello said that May’s tonnage reading represents a positive step forward, but noted that freight volumes remain mixed across the industry amid continuously rising fuel prices and a weak economy.

“The fact that tonnage increased on a month-to-month basis for the first time in four months, as well as achieving its largest year-over-year gain since February of this year, is quite positive,” Costello said. “However, year-over-year comparisons continue to reflect the weakness of 2007 rather than robust growth in 2008.”