Not to steal the thread, but I drive up Route 7 frequently on one tractor or another. The breakdown lane is 8' wide. I find most drivers go at speed limit passing. Typically they give only a foot, or two leeway as they pass at fifty MPH. Some travel much faster than that, and seem to speed up as they pass. Sometimes these are alpha drivers demonstrating how close they can get at 70 MPH passing. As I install more and more flashing lights it seems to get worse. I've developed the practice of staying in my lane until drivers slow behind me, then move over to allow them to pass.
By accident I discovered magical influence. I take a small sapling, place it crossways of the tractor in the rear. I let leaves stick out a couple feet past the tractor. I don't know what it says to drivers in a hurry, but it works! Those passing at seventy MPH move to the other lane to do so. Others slow down to pass.
Willie