At a road-works site, a temporary sign shows an arrow pattern directing traffic to merge left because the right lane is closed ahead. What is the correct response?

1. Begin merging into the open lane in good time, adjusting speed to fit safely into a gap
2. Continue in the closing lane as long as possible, then force your way in at the last moment
3. Stop completely until the lane reopens
4. Ignore the temporary sign in favour of the original permanent road markings