Was it human or technical error? The police are investigating the case of a driverless bus that collided with a house wall.

One day after the serious Heidelberg accident with a driverless bus, the search for the cause is underway. “It is being determined whether human error or a technical defect was the cause,” said a police spokesman on Thursday. In the accident on Wednesday, 19 passengers were injured, one woman seriously.

The heavy-duty bus had rolled about 100 meters down a slope without a driver and crashed into a house. The driver had previously got out to check for a door defect.

The residents of the house were lucky. The bus drilled a hole in the wall of the living room where a mother was with her child. But the two escaped unscathed. They jumped to their feet because of the noise the bus made when it hit two cars. “It could have been worse,” said a police spokesman.

According to the police, the bus driver got out because a rear door could no longer be closed. He wanted to fix the defect manually because the open door would have prevented him from continuing his journey. The driver was in shock. The bus was recovered on Wednesday evening using heavy equipment. Experts are now examining him. Among other things, the tachograph is evaluated.

According to initial police estimates, the damage is in the six-figure range. The bus alone suffered around 80,000 euros in damage, the damage to the makeshift house and the cars have not yet been quantified.