I would separate 2 issues.
I own small utility trailer, what most of the time is frame riding 1' above the pavement. Had people running into it as it is low visibility. So lately I put a 2 foot tall post on the end of it with licence plate on it. Helps in visibility a lot.
Than having 5-6 lanes freeways in my county, I never see semi-truck driven on right lanes. CA has lower speed limit for trailer, so semi truck block center of freeway big time, yet nobody gives and when they overlook right turn, they don't hesitate to cut-in abruptly in much faster traffic on the right lanes.
Can't fix stupid.