The speeds are appropriate for the roads generally. I mean, at the lowest level speed limits are a matter of social consensus so the broad public is tautologically correct.

The problem is that knocking the magic number on the sign down by 5-15 and then simply not enforcing it too seriously results in less screeching Karens harassing the politicians who then harass the bureaucracy than taking a hard line about "well akshually this is the engineered speed for the road".