Commercial Motor Vehicle Consulting (CMVC)’s Parts Aftermarket Sales Leading Indicator (PLI) fell for the ninth consecutive month, as the August Index decreased 0.8% from July. CMVC says this signals that parts aftermarket sales will expand at growth rates below trend in the coming months.

“PLI has fallen to a level signaling the growth rate of parts aftermarket sales will be below trend in the coming months and trend is defined as the long term growth rate of the commercial vehicle population,” said Chris Brady, president of CMVC. “Strong new and used truck sales over the past 12 months have resulted in new and used truck operators returning the average age of their fleets back to a norm, which would support growth of parts aftermarket sales at trend rates, but the downward trend in fleet capacity utilization indicates the rate at which the truck population is depreciating is slowing to levels dampening parts aftermarket sales below trend.

“For example, within the for-hire trucking sector, the transition of freight volumes from carriers’ brokerage operations to using their own tractors in order to maintain high truck utilization has had the effect of reducing the utilization of trucks by third-party carriers,” Brady explained. This slowdown in truck utilization has resulted in a decrease in the rate at which trucks depreciate, which in turn has had a dampening effect on sales in the aftermarket for truck parts, he said.