The Importance of Checking the Trailer Supports and Clearances

The iron trailer supports are up and the trailer is resting on the tractor. Make sure:

A. There is enough clearance between the upper and lower fifth wheels.
B. There is enough clearance between the tractor frame and the landing gears.
C. The safety latch is in unlocked position.

Final answer:

A trailer bouncing slowly on the highway is likely nearly empty because the lack of cargo weight leads to less damping in the suspension, resulting in more pronounced movement. So, option B is correct.

Explanation:

When observing a trailer on the highway and noticing that it is bouncing up and down slowly, it is more likely that the trailer is nearly empty. A heavily loaded trailer would usually have less bounce because the weight of the cargo would dampen the movement, making the suspension less prone to bouncing.

An empty trailer, on the other hand, has a higher center of gravity relative to its weight and lacks the mass to absorb road irregularities, leading to more pronounced and slow bouncing. In contrast, a heavily loaded trailer would show a more stable motion with less pronounced bouncing due to the weight pressing down on the suspension, which absorbs the road shocks more efficiently.

Therefore, observing a slowly bouncing trailer is an indication of it being lightly loaded or nearly empty. The lack of weight results in reduced damping of the suspension system, allowing the energy from bumps or road unevenness to cause more movement in the trailer structure. These observations are crucial for safe driving practices and can help inform decisions regarding speed and distance when driving near such vehicles on the road.