Sorry about the delay...again. Anybody have an application for Procrastinators Anonymous...send it to me, when you get around to it. :-D
David Hembrow was the closest, it is actually for grooves on shoulder. I call them rumble strips, the idea being that they are supposed to wake a driver up before they run completely off the road. Why anyone would be riding bicycle that far off the main part of the road I have no idea. This is a very monotonus stretch of road in the middle of nowhere South Carolina in the years I have driven this road I have seen only small number of cyclists, none riding on the shoulder.