The following graph shows heavy truck sales since 1967 using data from the BEA. The dashed line is the June 2020 seasonally adjusted annual sales rate (SAAR).
Heavy truck sales really collapsed during the great recession, falling to a low of 180 thousand SAAR in May 2009. Then heavy truck sales increased to a new all time high of 575 thousand SAAR in September 2019.
However heavy truck sales started declining late last year due to lower oil prices.
Click on graph for larger image.
And then heavy truck sales really declined towards the end of March due to COVID-19 and the collapse in oil prices.
Heavy truck sales were at 305 thousand SAAR in June, up from 282 thousand SAAR in May, and down 42% from 527 thousand SAAR in June 2019.