I was down in Florida visiting my dad and my old hometown, and I noticed that the speed limits are higher down there. In Maryland, we have highways that are 55, 60, and 65. I drove three hours on the Florida Turnpike at 70 (that was the speed limit). Many of the non-highways are also higher. Many of the non-highways were 45 and 50. Of course, those "back roads" also tend to be wider (many of them 3 lanes each way). With the higher speed limits, there were still many people passing me, but not as many as usual. The pressure to speed was much less with higher speed limits.
One more thing. I was driving my father's wife's car, and it doesn't have cruise control. Maintaining speed is much harder without cruise control. I use cruise control all the time. I just have to watch myself on hills so I don't speed up too much going down hill. Cruise control would have been perfect in Florida because there are no hills. Instead, I found myself going up and down in speed, never quite sticking to the speed I wanted.