Speed limits are not about limiting freedoms either. Highways are designed to standards design speeds. A freeway is designed to 60 mph design speed so grades, curves and banking is designed so vehicles can drive under control, stop when needed and have appropriate sight distance to minimize fatalities. Usually the speed limit is eqyal to or 10 mph more than the design speed. The spped limit is not some number politicians pick to limit driver freedoms.
But if the only person it's affecting is the driver, then it's limiting my freedom to drive 100 mph if I want. Now, I may or may not hurt someone else, and in the event I do, then I deserve prosecution. That's pretty much the same argument for legalizing marijuana and other drugs.