Issue being, people are always going to drive the speed they feel safe at. A sign, a rule, a law will do nothing to change that, unless you have a pig on every corner enforcing them perfectly. The way you change that is to ~not make the roads feel safe at faster speeds~. Fewer, narrower lanes and traffic calming features will do more for the issues than any speed limit signs will.
At the end of the day, a straight, flat, multi-laned road gives the feeling of safety at high speeds. I won’t say this is THE intent, but at very least is a side effect of the multiple lanes in each direction. Lower that to a travel lane in each direction and a turning lane. Add some medians. Add a chicane or two. Suddenly people drive slower because that’s what the road actually supports.
None of those things individually have any impact on the game. And none of them are likely to ever make it into a game by a company like Bethesda. The fact that you’re nitpicking these kinds of things, with no real basis, really makes you wonder the actual reasoning behind your post.