Van company Safety Officer reported the van drivers were not properly trained regarding FAA airport rules for driving on the tarmac. The drivers caused a taxiing aircraft to stop abruptly.

Narrative

At approximately XA:00; a driver of a van was attempting to pick up aircrew from the green ramp on ZZZ. The driver was unfamiliar with protocols and procedures of driving on an airport. As a result; the driver of the van entered a non-movement area without any authorization. The van driver located a 2nd van from the organization and proceeded to follow it to the pickup area. The driver of infraction then relieved himself as the driver. Upon departing the ramp with the aircrews; the two vans approached the path of a taxiing aircraft that appeared stopped. As the vans proceeded past it; the aircraft began moving and had to quickly stop. Both vans then exited the airfield; and returned home. The primary cause of the incident was lack of training for the driver that committed the incursion. As a result of the incident; collective training will be conducted of Airport markings and procedure for any individuals who will be operating a vehicle on an airfield. Additionally the unit will identify; train and certify select individuals who will be the sole operators of vehicles near or around airfields on all TDY events.