The actual driving road rules state, you only need to be in the left hand lane (when driving in a multiple lane road) when the speed limit is 90 km/h or more unless you are overtaking, turning right, making a U-turn, avoiding an obstacle or driving in congested traffic.
It is an offence to drive in the right lane if none of the above criteria are occurring. The only other time it is illegal to drive in the right hand lane is the speed limit is below 80km's and there are signs stating KEEP LEFT UNLESS OVERTAKING.
