The roads around the course must follow a strict re-opening schedule. We have worked this out so that even if someone was just continually walking fast, they will be able to finish the race on the actual road surface of the route.
However, anyone moving around the course at slower than 6 hour pace (that is slower than 4 miles an hour), may be told to move on to the pavement and in effect regard themselves as a pedestrian.
In addition, there will be cars and ambulances on the road if something happens or you are unable to finish.