Students who have finished their senior high school year in Sweden traditionally pile into the back of trucks and ride around town, dancing to blaring music. Often, a great deal of alcohol is involved.
On Thursday, police in Västerås said enough was enough after two students fell off one of the trucks and onto the road. They were rushed to hospital, but did not suffer any serious injuries.
A quick appraisal of the other students, however, led police to take action. They ordered all the trucks to leave the town centre and all the passengers to disembark.
"We decided to cut short the cortege immediately as the level of drunkenness was so high, and not least because of the two students who fell onto the street," Thomas Gustafsson of the Västmanland police told the TT news agency.
He added that things were usually messy at this time of year, but that this year hit a new low.
"The police on duty today said that it's worse than ever before."
In Stockholm and many other parts of Sweden, similar celebrations have been underway throughout the week. Many streets are littered with empty bottles and cans, with some trucks trailing a small river of spilt beer behind them.
IN PICTURES: See the students parading through Stockholm, 2013