Business Safety Intermodal Traffic Rises 3.2% for Week Bruce Harmon/Trans Pixs August 17, 2012 4:30 PM, EDT U.S. intermodal traffic rose 3.2% last week from a year ago, the Association of American Railroads reported. Container traffic for the week ended Aug. 11 rose 4.6% to 213,083 units, while trailers fell 6.1% to 29,947 units. Railroad carloads excluding intermodal dropped 1.2% to 289,172 units, AAR said. Railroad volume is considered an important economic indicator. Intermodal traffic, which tends to be higher-valued merchandise than bulk commodities, uses trains for the long haul and trucks for the shorter distance at either end of the trip. Ìý