I am usually going 5-10 mph over the speed limit on city streets and 15-20 mph faster on highways. I don't travel in the middle lane so if I'm not going fast enough for someone, they can just go around me. If they refuse to do that, I just slow down.
I keep slowing down until they go around me. If they are driving erratically I make a turn or pull into a business parking lot. If they follow me I would have already hit 911 ready to hit the 'call' button and likely go ahead and push it at this point. Big thing is to not drive to an isolated place.
Turn the parking light on for half a second. If that doesn't work, I take my foot off the gas pedal and coast. I haven't coasted quite to a stop yet, but it could happen. I'M driving my car, I'm not letting some impatient a$$hat behind me drive it for me.
If I am driving below the speed-limit I will gently accelerate to that, (if possible and safe to do so!) but will not break the limit for someone else.
Often that seems to do the trick; but if not they will just have to wait until feasible and safe for them to overtake.
