Mom used to talk about how 151 from home to Dubuque was considered a major highway, yet was only two lanes and had CURBS on the sides. She said people would lose control, hit the curbs and fly off into the next life. This was in the days before seat belts too.This was in the 70s in the muscle car era. The speed limit was 70 until the 55 limit came in. Even at 55 to 60, those roads required your full attention.