Engine brakes are required for slowing heavy loads, especially on long downhills. If you don’t use it the brakes will quickly overheat on a long downhill and become useless. [This](https://en.wikipedia.org/wiki/2019_Lakewood_semi-truck_crash) is what happens when a trucker doesn’t use engine brakes and overheats the service brakes. This driver also bypassed more than one runaway ramp.
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