I was born and raised in the Upper Penninsula (UP or yoop as we always call it) and I can tell you that a couple hours of driving at 55 mph sucks.
It sucks even more on the Seney Stretch (the most boring road in the state) http://www.atlasobscura.com/places/the-seney-stretch as that is about 25 miles of perfectly engineered straight road to no where, and there ain't nothing around but swamp and trees.
Serious temptation for cruise control and let the steering handle it self while RV drivers use the bathroom, or go hang out at the table in back for coffee time. You know it's happened, it was in the news.
Anyway, based on the actual speeds people drive when not being stalked by the state highway police, and the total lack of any reason to drive so damn slow when there is nothing around for miles, the Michigan govt finally had to listen to the old people that were young and getting their drivers licenses during the Vietnam War and have been pissed ever since about the 55 limit. Well they finally got old enough to get elected, and the speed limit is going up
In places where at least 85% of the drivers were at 65mph, and the engineers had ZERO reason to require slower speeds (sharp curves, steep hills) that double nickle is OUTTA HERE!
900 miles of highway are getting a boost to 65, and the interstate North of Saginaw is now 75 mph
Raised limits are happening "where speeds could increase based on 85th-percentile speeds (the speed at or below which 85 percent of traffic is moving) and the results of engineering and safety studies."
New speed limits will be posted on those three routes by mid-May. MDOT also will begin installing sign overlays reflecting the new 65 mph speed limit for trucks and school buses on state roadways with posted speed limits of 65 mph or greater. The new maximum speed limit for trucks and school buses was another change prompted by Public Act 445.