It is prohibited to make a U-turn:

1. When he drives a vehicle longer than eight meters.
2. Correct answer: When the turn cannot be seen by a driver from any other direction.
3. When he is in a two-way roadway.
4. If a road sign prohibiting left turn is placed.

WhyYou may not make a U-turn where drivers from any direction can't see your vehicle. A 'no left turn' sign alone doesn't prohibit a U-turn.