A Trailer with "Spring Brake" Priority and Observation of Bouncing Trailer

Understanding the Braking System with "Spring Brake" Priority

Final answer:

In a vehicle with a trailer, "spring brake" priority means the trailer's spring brakes will release before the trailer service brakes will operate. Regarding the observation of a trailer bouncing on the highway, it suggests that the trailer is nearly empty, as an empty trailer lacks weight to stabilize and dampen its bounce.

Explanation:

The subject of this question involves the braking system of a trailer, which is pertinent to the field of Engineering, particularly focused on automotive engineering. The term "spring brake" refers to a type of parking brake used in heavy vehicles, like trucks and trailers, which uses spring force to apply the brakes. When a vehicle with a trailer is equipped with "spring brake" priority, it allows the trailer spring brakes to release before other components of the braking system come into play.

Considering the options provided:

The towing vehicle service brakes will operate.

The trailer service brakes will operate.

The trailer spring brakes will release.

The trailer service brakes will release.

The correct answer to this question is that a trailer with "spring brake" priority allows the trailer spring brakes to release before the trailer service brakes will operate. This feature ensures that in the case of a loss of air pressure, the spring brakes remain applied to secure the vehicle, while the service brakes (used for normal braking during driving) can still be controlled independently.

Now, concerning the observation about the trailer bouncing up and down slowly on the highway, it is indicative that the trailer is likely nearly empty. A heavily loaded trailer typically has less bounce due to the weight pressing down on the suspension system, which dampens movement. In contrast, an empty or nearly empty trailer would bounce more due to a lack of weight to stabilize it.