Truckload linehaul rates paid by shippers increased again last month, while intermodal costs were mixed, according to two new reports from freight payment processor Cass Information Systems.

The Cass Truckload Linehaul Index rose 0.4% in August from July to 125, the third straight monthly increase, as new contract rates continue to filter into the index even though spot market pricing is down.

The reading is the best since April and a 3.7% improvement compared to August 2014. It's expected to steadily increase, according to investment firm Avondale Partners, which provides analysis of index.

“We expect the decline in industrial freight flows, especially related to oil and gas exploration, to be more than offset by a stronger consumer backdrop,” Avondale said.

However, Avondale has lowered its prediction for linehaul rate increases for 2015 from a range of 4% to 9% to a range of 3.5% to 5.5% for several reasons:

• The relaxation of the 34-hour restart rule (drivers must no longer must include two 1 a.m. to 5 a.m. rest periods), added approximately 1% to the nation's over-the-road capacity.

• Several significant pay increases have allowed many carriers to decrease their unseated truck count, which effectively increases the number of trucks on the road.

• The slightly younger age of the nation's truck fleet has increased capacity slightly, as new trucks spend less time in the shop.

• The dramatic fall in rig count has increased the pool of available drivers while decreasing the demand for industrial freight.

The Cass Truckload Linehaul Index is an indicator of market fluctuations in per-mile truckload pricing. It isolates the linehaul component of full truckload costs from other components, such as fuel and accessorials, providing a reflection of trends in baseline truckload prices.

Meantime, the Cass Intermodal Price Index in August fell 1.9% year-over-year to a reading of 128.1, the eighth straight monthly drop. It improved 1.2% compared to the month before and posted its second straight monthly gain following a 2.9% surge in July.

The drop in diesel prices has challenged demand for intermodal services, according to Avondale, as many loads, mostly shorter haul, have shifted to truckload this year.

It is forecasting domestic container shipments may grow at a low single digit rate in 2015, but that is dependent upon demand in longer lengths of haul growing fast enough to offset the loss of volume in shorter lengths of haul, particularly in the eastern U.S.

The Cass Intermodal Price Index is an indicator of market fluctuations in per-mile U.S. domestic intermodal costs, that includes all costs associated with the move, such as linehaul, fuel and accessorials.

Data within both indexes is derived from actual freight invoices paid on behalf of Cass’ clients, which totaled over $23 billion in 2013.