Employee skill determines how well they perform a task, and how satisfied the customers are. It doesn’t seem that driver skill really matters, though. What’s going to happen - they crash and lose your inventory? (I hate this idea, please don’t do it, devs lol)
But I did have an idea I liked. Drivers can be assigned from a van to a possible a large semi-truck (which has been lightly teased by devs). What if the driver skill level determined how big of a rig they could drive?
25% - van
50% - small truck
75% - large truck
90% - Semi