The following graph shows heavy truck sales since 1967 using data from the BEA. The dashed line is the August 2016 seasonally adjusted annual sales rate (SAAR).
Heavy truck sales really collapsed during the recession, falling to a low of 181 thousand in April and May 2009, on a seasonally adjusted annual rate basis (SAAR). Then sales increased more than 2 1/2 times, and hit 479 thousand SAAR in June 2015.
Heavy truck sales have since declined – probably mostly due to the weakness in the oil sector – and were at 331 thousand SAAR in August.
Even with the recent oil related decline, heavy truck sales are only about 10% below the average (and median) of the last 20 years.