I'm fairly ignorant with regard to safety equipment on tractor-trailers. Do they not build the brakes on these trucks to handle grades with a heavy load, within reason? Or, are they solely dependent on starting off slow, and keeping it geared down, with brakes as a supplement only?
drum brakes, retreaded tires, non-syncrhonized manual transmissions, and most trucks are older than the people driving them 70 hours a week