https://www.youtube.com/watch?v=QLl9NCJvZjw
This is nuts!
Vibration stabilizers are commonly used on transmission power lines to minimize or eliminate conductor galloping and other movement from the wind. They look like barbells and usually are near each string of insulators. Such devices also have been used on street light arms to keep them from vibrating (usually on tall poles or in windy areas) as well.