I drive a heck of a lot of miles every month. I range all over SoCal, and into the southern reaches of NorCal. Include some of the western bits of Arizona and Nevada and you get the picture.
Get outside of the L.A metro area and drivers seem to have engaged their brain. Yea, you get the occasional fool who wants to do 100 in a 70, but you find them everywhere. Mostly traffic runs about 10 miles over the speed limit, and the CHP is okay that. As long as you don't cut in and out and drive like an idiot, that is.
Inside the metro area the stupid gene expresses itself. Every kind of rude and dangerous behavior is seen within 5 or ten miles of travel. So if you figure you drive 100 miles the poor drivers seem to be everywhere.
Here you must drive defensively but aggressively at the same time. Sound contradictory, but it isn't. By aggressive I don't mean cutting folks off, tailgating or rudely not allowing others to change lanes or merge on to the highway (the most common sins). It's hard to really describe the style unless you live here.
Back to the OP's original question. If I'm tailgated, regardless of the type of road, I just start slowing down, generally by just taking my foot off the gas. Except for the total idiots about the time I've dropped my speed 5 or 10 mph they will pass. Now you get the fools who think they have the right to cut you off when they pull ahead of you, but as they pass I usually cover the brake.
Another hugh problem here is what we joking call the "low blinker fluid syndrome" Folks, whether out of laziness, stupidity or rudeness frequently forget what blinkers are for. It's as important to watch the driver as it is the taillights.