Final answer:
When towing a trailer, one should steer gently and smoothly and slow down before turns. If a trailer bounces slowly on the highway, it's likely nearly empty as heavy loads dampen such movement.
Step-by-step explanation:
When pulling a trailer, you should steer gently and smoothly to maintain control and prevent accidents. Sudden movements with the steering wheel can cause the trailer to sway or jackknife, especially at high speeds. Moreover, it is recommended that you slow down to a safe speed before entering a turn to allow for the extra length and weight of the trailer, which affects how it handles during turns. If you encounter a freight truck with a trailer on the highway that is bouncing up and down slowly, it is more likely that the trailer is nearly empty. A heavily loaded trailer would have less bounce due to the weight damping the movement.