Austrian police have stopped a van crammed with 42 migrants and arrested the Romanian driver, who they say had driven them nonstop from the Serbian-Hungarian border.

Police in Lower Austria province said another driver alerted them Friday to the Bulgarian-registered vehicle, which was swerving in front of him on the A4 highway east of Vienna. Officers stopped the van, and found 42 people locked into a 6.5 square-metre space inside the vehicle without ventilation.

Police said Sunday that some of the Afghan and Syrian citizens showed signs of dehydration after eight hours in the van in hot summer weather.

The 37-year-old Romanian driver was arrested. Police say he had planned to drop the migrants in Rannersdorf, outside Vienna, and is suspected of involvement in other people-smuggling operations.