Sure, there’s some truth in that.
What about situations (I saw them in my old state of Ohio) where just by virtue of statute, that a state route, with a speed limit of 55 on one side of the street, has a speed limit of 35 on the other side of the street simply because that side of the street is in the city limits of a municipality?
You can’t tell me that one side of the street is safe at 55 but the other side of the same street is only safe at 35...
You’ve given me an extreme example of one situation that is pretty atypical with respect to highways. In that case, which I do not have access to any information in which to accurately base an opinion, I can only assume there are two different jurisdictions with respect to the establishment of those two different speed limits, and each made their judgement regarding the posted speed limit for different reasons.