While fairly rare, I am occasionally greeted from behind by one of these drivers... like this morning on a narrow high speed (50 mph) arterial road that I need to take to get to work. This road has a very rough shoulder which is unridable, so I always control the entire right lane, which is about 10 feet wide. There are four lanes total, so drivers can merge left to pass.
Today, the driver of a Cadillac Escalade pickup thingy gets right up on my tail and starts honking. I ride this section as quick as I comfortably can, so I was going between 20-24 mph. He / she left less than a car length between their vehicle and mine, so I looked back and signaled for them to stay back, while holding my speed. (think slow / stop signal, with open palm pumping straight back several times) The driver never backed off, found a chance to change lanes, and passed me a little close while cutting back into the right lane and honking a few more times.
It seems to me there's not much more I could have done. Do you have any good techniques for dealing with this situation?