Consider the situation in the following diagram:
Car A is in the left lane approaching an intersection with a slip lane. The car wishes to turn left, but the slip lane is obstructed by a fallen load.
Question. Is it possible for car A to turn left at this intersection? If so, how?
Answer. Yes, it is possible to turn left. Because the slip lane is obstructed, car A can approach the intersection proper and turn left at the lights.
Australian Road Rule 28 (‘Starting a left turn from a multi-lane road’) says:
(1A) A driver turning left at an intersection from a multi-lane road that has a slip lane must approach and enter the intersection:
(a) from within the slip lane; or
(b) if there is an obstruction that prevents the driver from entering the intersection from within the slip lane—from within the left lane.