How safe is the bike/pedestrian underpass at Goodwood?

Over the last few days I have had two people ask me to investigate the safety of persons using this underpass. The path is the shared use area for train commuters, bicycles on the Mike Turtur bikeway and other persons just trying to safely cross under the rail line. The signage requests bike riders should dismount and walk through the area. My understanding is that this does not happen often enough. One person even observed the postie using the path on his motor bike!  Any observations or suggestions are welcome.