The Automotive Aftermarket Industry Association (AAIA) collaborated with the Heavy Duty Distribution Association (HDDA) on the second-edition 2006 Medium Heavy Duty Aftermarket Profile, which stated that sales have increased for a variety of reasons, including rising Class 4-8 vehicle sales, increases in miles driven, growth in truck registrations and the nation’s dependency on trucking for logistics.

Following relatively flat growth in 2001-2003, when annual increases were less than 1%, medium and heavy duty aftermarket sales picked up in 2004, the study reported.

The report combined industry data from AAIA research and government and independent research supplier databases. It was last published in 2000.