Under Article 43 of the Road Traffic Safety Law, in which of the following situations is a motorcycle rider strictly prohibited from overtaking the vehicle ahead?

1. When the vehicle ahead is turning left, making a U-turn, or is already overtaking another vehicle (前车正在左转弯、掉头、超车时)
2. When traveling on a multi-lane one-way street with broken white lines
3. When the vehicle ahead is traveling 10 km/h below the posted speed limit
4. When the road has high daytime visibility