

Because when the road is built for a safe speed target of 65, then the limit is set at 55 instead, yeah you get people who are breaking the legal limit but not the actual safe speed.
Edit: forgot a link: https://www.fhwa.dot.gov/design/standards/151007.cfm
tl;dr: design speeds and speed limits are not necessarily related. “Selection of a posted speed is an operational decision for which the owner and operator of the facility is responsible.”
I think the N100 units are still the best value.