Intermodal volumes jumped 4.5 percent in in the second quarter of 2015, with international shipments surpassing expectations, according to the Intermodal Association of North America (IANA)’s second quarter Intermodal Market Trends and Statistics report. Despite some softening due to declining trailer volumes, domestic containers buoyed the overall domestic market segment with 3.5 percent growth.

International container volumes grew by 6.8 percent.

“International volumes displayed one of the largest increases since IANA began keeping records in 2000,” said Joni Casey, president and CEO of IANA. “While much of the strong performance in Q2 was due to the recovery from the first quarter’s port congestion issues, strengthening imports also played a role in pushing international volumes higher. We are also optimistic that the domestic market will continue to show gains, as the over-the-road segment begins to tighten.”

The seven highest-density trade corridors, accounting for 65.8 percent of total intermodal volume, rose four percent in the recent quarter, just below the 4.5-percent industry average.

Growth rates for each individual corridor varied widely. The intra-southeast corridor, positively impacted by stronger imports through southeastern ports, led the way as intermodal volumes jumped 23 percent during the quarter. The South Central and Southeast regions saw strong international growth, surpassed industry averages, while the Mountain Central and Eastern Canada regions failed to see intermodal volumes climb.

Excluding those four areas, most regions recorded intermodal growth in line with the industry average, according to IANA’s figures.

Intermodal marketing companies posted strong year-over-year second-quarter volume growth. As intermodal loads jumped 4.5 percent, IMC highway volume soared 8.2 percent, which was three times the pace of overall highway trailer loads.