I'm not suggesting to make poor quality roads. I am suggesting to not put up a 25mph sign on a road wide and straight enough to feel safe going 50mph. A main road near me is such a 2 lane road, 4 lanes widths wide, and is completely straight, but marked 25mph. It's no wonder most people go at least 10-15mph over. I do so unconsciously if I don't pay attention to the speedometer.