ROME — A car plowed into a group of young German tourists as they crossed a road in northern Italy early on Sunday, killing six people and injuring 11 others, four seriously, Italian officials said.

The driver, a 27-year-old man from the area, showed a blood-alcohol level nearly four times Italy’s legal limit, according to the prosecutor’s office in Bolzano, a city in the South Tyrol area of northern Italy. The man, identified by the police by his initials, SL, was arrested on suspicion of vehicular manslaughter.

The victims were part of a group of youths, aged 20 to 25, who had booked a five-day vacation through a travel agency. Most were German, but officials said one of the injured was Italian.

The vacationers were returning from a night out at a pub and were hit while crossing a state road to reach their lodgings, said Arno Kompatscher, the region’s president. They had used a public shuttle service established in the region so that young people could go out and have fun but not drink and drive, he said.