At least 15 people were injured, four seriously.
The suspect, who lived in his car, was drunk and was going to undergo a psychological exam, said state interior minister Roger Lewentz.
The car sped more than half a mile through the quaint medieval town center and past the town’s Christmas tree to maximize casualties before being cornered by police, he added.
The video posted online showed a man being held on the ground by police next to a silver-gray vehicle on a bike path. Another showed the chaos: ambulance and paramedics on one Shopping street littered with rubble.
A witness quoted in local media described a stroller that flew in the air as the car flew through the market area. The dead also included a 73-year-old woman, a 45-year-old man, and a 25-year-old woman.
In conversation with reporters, the city’s mayor, Wolfram Leibe, was overwhelmed by emotions.
“We often see pictures like this on television and think:” That can’t happen to us here, “he said,” but now it has happened in Trier. “
He called the scene “just awful”.
“There was a sneaker and the girl it belonged to is dead,” he said, fighting back tears and handing the microphone over to a colleague.
“I don’t know the perpetrator’s motivation,” said Leibe, adding that he “kept my fingers crossed” and that all the injured survived.
Leibe said the police were there five minutes after the first phone calls and experienced “wild chaos”.
The authorities said the perpetrator was a local from the Trier-Saarburg district.
“What happened in Trier is shocking,” tweeted government spokesman Steffen Seibert. “Our thoughts go with the relatives of the victims, the numerous injured and everyone who is currently on duty to look after those affected.”