Which vehicle must wait when half the roadway is closed because of roadworks?

Your answer is correct. According to German traffic rules, when half of the roadway is blocked due to roadworks, the vehicle on the side where the roadworks are located must wait. This is because the available space is restricted, and the vehicle closest to the obstruction should yield to allow the other vehicle to pass safely. The other options are incorrect: the vehicle on the unobstructed side does not have to wait, and the size of the vehicle does not determine who waits in this situation. Remember this rule to ensure safe and orderly passage through narrow or partially blocked road sections.