My sympathies. Your post gave me an idea. Why not put portable speed bumps across the road ahead of the workers? Put one maybe 30 feet after the first “Reduce speed” sign. Put another one further down the line. That would hopefully alert distracted drivers. Whadda'ya think?
Oh, and I looked it up. Portable speed bumps do exist.
They do but not all vehicles have the clearance necessary to absorb them.
A friend has a Harley 3 wheeler and he tore out his exhaust system on a typical parking lot speed bump that he thought he could clear.......
Some freeways have ridges on the shoulder that sound like brrrrrrp, brrrrrrp, brrrrrrp when you run over them. Something portable like that could work but then again, not even stop lights or signs at intersections prevent accidents.......