The Safety Investigation Authority said its probe into a fatal bus crash in Kuopio - that claimed the lives of four people and injured many others in August - is largely complete.
The vehicle ploughed through cars before plunging off an overpass, landing on a train track below. Four people were killed and 22 others were seriously injured in the fatal accident.
On Friday Investigators said their probe revealed that several factors contributed to the crash.
Course of events
As the vehicle was approaching a motorway exit ramp, it was driving at about 90 km/h in a zone with a posted speed limit of 100 km/h. According to investigators, the bus only slowed down a little from that speed as it approached the railroad overpass, and that the driver realised the vehicle was going much too fast.
The driver told investigators that he noticed there were cars in the left lane - in the same direction that he planned to take the bus. The driver said he tried to brake in order to slow down the bus but he was unable to, and in order to avoid a collision he turned the steering wheel sharply to the right.
According to investigators, the speed of the bus was so excessive on the overpass that the driver was unable to turn, and the vehicle ploughed into five cars ahead of it and continued into the barrier. The vehicle careened off the bridge and onto the ledge by the train tracks below, coming to a standstill on its side.
The investigators said that as the bus was crossing the intersection it was going at least 50 km/h. But after measurement of the vehicle's tire tracks on the bridge and taking into consideration the distance it travelled after it smashed through the barrier, investigators suspect the vehicle was going much faster than that.
Diagnostics equipment aboard the bus, however, did not give investigators exact data on how fast it was travelling in the moments leading up to the crash, the safety agency said.
Bus driver's health, experience factors
The investigation also revealed that the bus driver's diminished health combined with an unusually heavy work schedule likely reduced his alertness behind the wheel that day.
The driver also had little experience with the particular model of the bus, making him unfamiliar with the controls.
The agency said their probe into the accident will continue and that it plans to issue a report which will include safety recommendations at the beginning of next year.