ARLINGTON, VA.— Retail, manufacturing and housing helped push truck tonnage up by 2.3 percent in May, according to The American Trucking Associations’ (ATA) advanced seasonally adjusted (SA) For-Hire Truck Tonnage Index.

Compared with May 2012, the SA index was 6.7 percent higher — the largest year-over-year gain since December 2011. Year-to-date, tonnage is up 4.5 percent.

According to ATA Chief Economist Bob Costello, the increase is due to a combination of sectors showing strength. The month of May saw factory output rise and and stronger retail sales. Plus, “the 6.8 percent surge in new housing starts during May obviously pushed tonnage up as home construction generates a significant amount of truck tonnage,” Costello added.

“While we heard good reports regarding freight levels during May, I have to admit I am a little surprised at the large gain in tonnage,” Costello said.

Costell also noted that “tonnage continues to outpace the number of loads hauled as heavy freight (e.g., housing construction materials and sand and water for hydraulic fracturing) is outperforming box trailer (i.e., dry van) freight.”