Vehicles try to avoid getting in the queue on the south eastern to travel north on the southern motorway by continuing to the great south road and doing a U-turn. I have seen cars and trucks do a U-turn here.
This is a problem for vehicles following as they often have to stop. Sometimes the vehicles doing a U-turn also have to stop due to south bound traffic on the great south road turning left onto the eastern arterial route being in the way.
This would be solved if "No U-turn" was implemented