I know that in the tunnel that goes under Sydney Harbour they can record your speed. It gets displayed on one of those overhead displays if u r going over the limit. They can also cut into your car radio and let you know if your speeding or of breakdowns etc. They send this info to the NSW Road Taffic Authority so if they can issue infringements. So if it can be done there they can do it here both tunnels look to be similiar (internally anyhow)