Final answer:
In the traffic separation scheme, vessels are not allowed in the separation zone unless crossing at a near right angle for safety and to minimize the risk of collision.
Step-by-step explanation:
In a traffic separation scheme, certain rules must be followed to ensure the safety and orderly movement of vessels and prevent collisions. The separation zone serves as a divider between opposing streams of traffic, typically in busy maritime routes. As per the International Regulations for Preventing Collisions at Sea (COLREGs), vessels are generally not allowed to enter a separation zone unless they are crossing it in a way which is as near to a right angle as is practicable and safe. This minimizes the time spent in the zone and reduces the risk of collisions. This rule applies regardless of the size of the vessel or its purpose; the objective is to maintain an efficient flow of maritime traffic and maximize safety.