I've actually found a really good solution to tailgaters: put very slight pressure on your brake pedal, enough to get the brake lights on, but not enough to act

I've actually found a really good solution to tailgaters: put very slight pressure on your brake pedal, enough to get the brake lights on, but not enough to actually cause any substantial deceleration. This will cause the tailgater to also slow down, but more than you because they have no way of telling how hard you are braking. The result is increased distance between you and them. Do that a few times and even the most persistent tailgater gets it and either changes lanes or stops riding your ass.