You are driving in NSW on a multi-lane road. Another vehicle wants to merge into your lane from the right. Under the zip merge rule, what should you do?

1. Speed up to prevent them from entering your lane
2. Let every second vehicle merge, alternating with your lane — allow the merging vehicle in if it is their turn
3. Always give way to the merging vehicle regardless of your position
4. Sound your horn to warn them they cannot merge