In this situation, is the driver of vehicle 1 obliged to drive to the right?

Explanation

Correct answer: Yes

Yes. Vehicle 1 must move right to clear a passage for the emergency vehicle. In congested traffic, drivers in the leftmost lane move towards the left edge, and those in other lanes towards the right. The aim is to clear a corridor, not necessarily to change lanes completely. Blue flashing lights alone do not define a moving vehicle as having emergency priority.