Can we put speed limits for cars based on a mathematical fourmula?

All roads have a base design speed. We could start with that and adjust up or down depending upon the driver. I’d also put driver’s reaction time into the equation. It’s not practical, but I like it.

Weather would need to be included as a factor since wet, icy or snow covered road surfaces do impact safe driving speeds.

I see this raising a related question: how would you quantify a driver’s level of distractedness at any given moment?