The van skidded in rainy conditions at around 8:30 am and slammed into a guardrail. The tunnel had to be closed until around 10:15 am and there were serious delays on the S1.
According to the Austrian air ambulance a 45-year-old woman who had been in the back of the van was seriously injured and had to be airlifted to hospital in Vienna. Five people with minor injuries were admitted to hospital in Baden.
Police spokesman Johann Baumschlager said that the driver of the van fled from the scene of the accident and has not yet been found. He described how the refugees were found wandering down the S1 after the accident and putting themselves and others in danger.
More than 40 refugees were taken to police headquarters in Schwechat and the investigation into the accident and the missing people smuggler has been handed over to Lower Austrian police.