Colorado drivers need remedial training on what "Keep Right Except to Pass" means.  

They also need remedial training on driving in the snow.  The roads are full of incautious drivers who think their 4x4 or AWD vehicle makes them invincible and they don't slow down on snowy/icy roads.  On the flip side, there are also a lot of overcautious drivers who slow down to 1/2 the speed limit if they even think they see a flake of snow.