the county put rumble strips in on a lot of rural highways and the local bike advocacy group got them to re-pave on the shoulders that had substandard shoulders, which they define as 4' wide. I was impressed. OTOH, I wish they had thought about it in the first place. One of the big downsides of rumble strips in the center of the road is that people are afraid to take their giant 4wd off-road vehicles across a few small bumps, so they pass too closely.

I met the Penn State professor that helped PennDOT evaluate rumble strips. His test involved riding a mountain bike down the rumble strip designs. So that's why they are so rough. He's an idiot in person too.