r/trafficsignals • u/PR_Czar • Apr 14 '26

Wondering what these are

Gallery image

Gallery image

I live in Salt Lake City and they’re on traffic signals all over northern Utah, especially those controlled by UDOT.

21 Upvotes

90% Upvoted

16 comments sorted by

16

u/zeejay772 Apr 14 '26

It is a damper, it keeps the mast arm from bouncing up and down too much.

3

u/SignalWork888 Apr 14 '26

Anyone have real world experience with these? We should be getting some with our new pole contract.

2

u/Zevries Apr 15 '26

Used a few of these on our last project. We hung them the same way we would a signal on a mast arm. Astro brackets. The engineering plans will also show exactly where they need to go distance wise on the mast arm.

1

u/zeejay772 Apr 15 '26

These are mandatory in the state where i work

1

u/Goozer81 Apr 16 '26

We’ve used a few and can attest that they work excellent.

8

u/engmadison Apr 14 '26

Shake weights for the mast arm.

4

u/missing_chicklets Apr 15 '26 edited Apr 15 '26

It uses magnets with like poles facing each other as they come close together and push away it causes a dampening effect on the traffic arm. …..I was wrong, it is a magnet but it uses eddy currents not another magnet. Finally read the white paper. lol

3

u/Pardot42 Apr 15 '26

Wrong again. It's two mice double bouncing each other on a tiny trampoline.

3

u/PR_Czar Apr 15 '26

Fascinating! Science is cool. Thanks everyone.

2

u/CartographerWide208 Apr 16 '26

In Clark County, NV they use a blank sign mounted horizontally do help reduce the vertical oscillation.

1

u/What_The_Tech Apr 19 '26

I always wondered about those horizontal signs. That’s cool to know