I've seen some MUPs that are "divided" for types of users. Pedestrians stay on one side and cyclists/skaters stay on the other. The idea is to keep pedestrians out of the "fast lane" for safety. In practice, pedestrians walk anywhere they want and cyclists get angry because "their lane" is subject to frequent infringement. The best MUPs I've ridden have no lines and everyone seems to know how to handle the mixed use.