Under Article 59 of the Implementing Regulations, when a motor vehicle travels at night and approaches a crest of a steep slope, a sharp curve, a blind intersection, or a pedestrian crosswalk, how must the driver use their headlights?

1. Keep high beams on continuously to illuminate blind spots
2. Alternate between high beams and low beams at least twice (交替使用远近光灯示意)
3. Turn off all headlights and sound the horn three times
4. Turn on hazard warning flashers and accelerate past the hazard