How would a tractor and its trailer maintain low speed during a long and steep descent?

1. Correct answer: By driving in low gear and relying on the engine’s compression braking .
2. By regulating the speed with the brakes.
3. By using the trailer’s brakes and locking the differential.
4. By operating the engine brake and driving in low gear.

WhyOn a long descent with a trailer, keep the speed low with a low gear and engine braking. That way the brakes do not overheat.