not that I know of girth ... I've lived in and around part of the egg run route for many a year now and I don't ever remember them closing any (except for perhaps New Brighton start point) of the roads off at all ... It's always appeared to be a "if you go out on the egg run route, then you take your chance".
i've not done that stretch of the run myself before, so i will e-mail the organizers of the egg run and find out tho
(unless someone else knows for sure?)