After evacuating passengers from a burning bus on an expressway, where must the driver assemble and lead the passengers to ensure their safety?

1. Move all passengers to a safe location at least 100 meters upwind (上风方向) from the burning bus, behind the roadside steel guardrail outside the expressway carriageway
2. Gather passengers immediately behind the burning bus's rear bumper to stay warm
3. Have passengers stand in the active adjacent travel lanes to wave down passing vehicles
4. Instruct passengers to sit on the expressway median strip between fast lanes