Limitation signs probably aren’t just like that. I don't know how there is in the world, but in Russia on such roads even 90 is scary to drive (there are holes, then tracks, etc. and if the holes are still fine, but tracks in the winter is the worst thing, even in the city). I drove as a passenger at speed 190, on a 4 strip, flat track, this speed is visible only on the speedometer, in sensations - about 100. Why drive at such a speed? Are you in a hurry to give birth or hunt? At this rate and the load on attention is strong, and the car is not very good. Comfortable speed outside the city without fatigue 90-110, and within the rules. On the serpentines I would generally put a post at the entrance, so that fools catch how much I drive, so constantly "right" dudes at the encounter, trying to finish overtaking (when either consistent everywhere or especially cool on the rises and blind turns). I never turn away, not my problems, that they have a brain lacking as an organ, it is easier for me to rip a buffer in case of something, than a multi-ton truck to throw into the square and lose both the car and the cargo, even for life is dangerous. So as the saying goes "He who has understood life is not in a hurry".