When negotiating continuous blind mountain curves and switchbacks, what is the standard safe driving procedure?

1. Drive in the center of the road to maximize turning angle
2. Sound horn in advance (鸣喇叭), reduce speed, keep strictly to the right side of the lane, and never overtake on curves (减速、鸣号、靠右行)
3. Overtake slower vehicles on right-hand blind corners where oncoming traffic is invisible
4. Turn off headlights to avoid distracting oncoming drivers