TL!:
"Where the speed limit is 55 and I'm supposed to slam on brakes because they want to cross the street in their own slow time."
Are you talking about "streets" or "curvy country roads".
If you are on curvy country roads, going around curves at 55 mph may not be such a great idea no matter what the posted speed. You might just hit a deer, or anything else crossing the road along with any country folk crossing the road.
Thing is safety is the responsibility of the car driver and if you are able to see how slowly someone is moving ahead of you, having to slam your brakes on means you are going too fast.
I'm still willing to go for a walk on a country road with you