When driving a heavy truck on an unlit mountain road at night and approaching a blind curve or crest, what headlight signal is required under Article 59 of the Implementation Regulations?

1. Alternate between high and low beams (远近光交替闪烁) at least twice to illuminate blind zones and alert approaching drivers
2. Turn off all headlights completely to preserve battery voltage for the horn
3. Keep high beams fixed on continuously throughout the corner to blind oncoming vehicles into stopping
4. Use only hazard warning flashers and turn off all forward driving lights