The amount of freight moved in June as measured by one gauge moved barely higher after surging in May, but it still managed to hit a record high.

The American Trucking Associations’ advanced seasonally adjusted For-Hire Truck Tonnage Index increased 0.1% in June from the month before after increasing 2.1% in May from April. The May hike was revised slightly downward from the 2.3% gain ATA reported on June 18.  

In June, the seasonally adjusted index equaled 125.9 versus 125.8 in May. June 2013 is the highest level on record. Compared with June 2012, the index surged 5.9%, which is robust, although below May’s 6.5% year-over-year gain. Year-to-date, compared with the same period in 2012, the tonnage index is up 4.7%.

The not seasonally adjusted index, which represents the change in tonnage actually hauled by the fleets before any seasonal adjustment, equaled 125.9 in June, which was 5% below the previous month at 132.4.

“The fact that tonnage didn’t fall back after the 2.1% surge in May is quite remarkable,” said ATA chief economist Bob Costello said. “While housing starts were down in June, tonnage was buoyed by other areas like auto production which was very strong in June and durable-goods output, which increased 0.5% during the month according to the Federal Reserve.”

“Robust auto sales also helped push retail sales higher, helping tonnage in June,” he said, “The trend this year is heavy freight, like autos and energy production, is growing faster than lighter freight, which is pushing truck tonnage up.”