After declining for three straight months, intermodal rates rose in August, according to a monthly report on truckload and intermodal pricing. The Cass Intermodal Linehaul Index, which is issued by freight auditing and payment firm Cass Information Systems and investment firm Avondale Partners LLC, shows that rates are now at the same level as the year prior.

Intermodal rates rose in August 1.3 percent over July's figures; an increase that Avondale said reflected "solid demand" during the month.

Meanwhile truckload rates continued their downward trajectory through 2012, according to the Cass Truckload Linehaul Index. In October 2011, truckload rates hit their highest levels since 2005; now, however, truckload rates are up only 1 percent through August on a year-over-year basis, according to the report.

The decline in truckload prices has been driven by slowing demand as well as a spike in diesel fuel prices. Rising diesel prices often lead shippers and third-parties to shift their freight to more fuel-efficient intermodal services. This conversion to intermodal often picks up once diesel fuel prices hit $4 a gallon. As of yesterday, the average price for a gallon of diesel fuel in the United States stood at about $4.13 a gallon.

The report measures pricing trends just on the linehaul portion of the movement and excludes the impact of fees and surcharges.