That is awful SR, sounds very similar to what happened to me on highway 6. I shudder to think what would have happened if there was someone in the left lane when I had to move into it to avoid a crash. Makes me angry too.
I found a trailer bumper sticker that is appropriate, but I feel the wording not NEARLY clear enough. Here it is:
Bumper Sticker For Horse Trailer Caution Horses To Gifts, T-Shirts, Stickers, & More - CafePress
I would change the wording to:
"Give us more room to stop you useless, ignorant, selfish bunch of idiots"
Throw a couple F-bombs in there somewhere and that says it all really.