What must vehicles do before crossing the tail clearance line in the domestic horseshoe?

Before crossing the tail clearance line in the domestic horseshoe, vehicles must check for aircraft and other vehicles. This requirement is critical for maintaining safety in the high-traffic environment of an airport. The tail clearance line specifically indicates an area where aircraft may have their wings or tails extending, and vehicles need to be vigilant in ensuring that no aircraft are crossing their path or that other vehicles are not already occupying that space.

By prioritizing this safety check, operators minimize the risk of collisions and potential accidents, thus ensuring the safety of both ground personnel and aircraft. Being aware of other entities in the area ensures compliance with standard operating procedures and the overall safety protocols set by the airport authority.