What happened
At the time of the incident, Runway 31L was designated as the only active runway for aircraft operations. Meanwhile, approximately nine snow removal vehicles were being utilized to clear snow from Runway 4L/22R. The drivers of these ground vehicles had been explicitly instructed to hold short of Runway 31L.
The Boeing 747, D-ABYO, was cleared for takeoff on Runway 31L. As the pilot began his takeoff roll, he observed a car approaching the active runway. Recognizing the potential conflict, the pilot initiated an aborted takeoff.
The driver of the car had mistakenly believed that Runway 31L was closed to traffic. Before entering the runway, the driver saw the aircraft and applied the brakes; however, the vehicle slid onto the runway surface. The aircraft and the car did not collide. However, the jet exhaust from the Boeing 747 overturned the car, which resulted in injuries to the occupants.
Findings
The primary contributing factor was a misunderstanding by the ground vehicle driver regarding the status of Runway 31L. Despite instructions to hold short, the driver entered the active runway believing it was closed. The subsequent interaction between the aircraft's jet exhaust and the grounded vehicle led to the overturning of the car and injuries to its occupants.