Under Article 51 of the Implementing Regulation, what must a driver do when facing a green traffic light if traffic ahead is congested?

1. Proceed into the center of the intersection and wait between the traffic lanes
2. Do NOT enter the intersection if the vehicle cannot clear it without blocking cross-traffic, even on a green light
3. Sound the horn continuously to force crossing traffic onto the footpath
4. Enter the intersection and shift into reverse if traffic remains stationary