Ever notice the Escape Ramps for 18 wheelers on step downgrades? And all the tire tracks in them.
At least some new road trucks are switching to disc brakes.
I drove a new company Mack truck before I retired a couple years ago. Disc brakes on ALL axles. No drums. It also had Mack's own engineered automatic (computer controlled manual) transmission. It worked very well.
With a good modern engine braking systems on an 18 wheeler, I barely had to use the brakes even when loaded heavy on the steep downgrades when obeying posted speed limits. But those drum brakes would heat up quickly if you mistreat them and then it feels as though someone greased your brake shoes.
