I'll be real, I really like the 55mph county highways compared to the 65mph interstate. At 55mph you're closer to the sweet spot for fuel efficiency (for most vehicles around 45mph is the most fuel efficient speed) so you get noticably better gas milage. The 70mph interstates are generally a bit scary because going 75-80 to keep up with traffic just feels too fast and I can feel how much harder it is to control my vehicle compared to going less than 70, plus the engine works noticably harder against the wind to maintain speed.

I also witnessed a crash where a vehicle was going 80ish in a 55 zone on a beltline. They lost control while passing a vehicle, hit the barrier then careened accross three lanes of traffic pinning another vehicle against the opposite barrier. Nobody died and it appeared everyone was largely uninjured (thanks modern crash safety standards!) but the woman in the pinned vehicle was trapped. Point is, going slower they would not have lost control, or if they did they would not have crashed as badly doing so