After a twenty-minute scheduled stop at a depot in Zawory, the bus – an Autosan H9-21 – began its return to Gdańsk with just two passengers.

Further along the route, large crowds of travelers boarded the vehicle at stops in Chmielno and in Kartuzy.

By this time, the overcrowded vehicle was carrying 74 passengers, far in excess of the maximum allowable capacity of 51 (39 sitting, 12 standing).

32 kilometers after the start of its journey and 500 meters before its next scheduled stop in Gdańsk-Kokoszki, the overloaded bus veered off the road and crashed into a tree while attempting to pass a Jelcz truck.

The immediate cause of the accident was found to be the explosion of the front right tire, with contributing causes given as: The tree which the bus struck was cut down in February 2008.