Three cars were involved in the crash, on a stretch of the E22 between Kalmar and Rockneby, in the southwest of Sweden.
According to Svenska Dagbladet, Kalmar police say the accident was caused when a trailer being pulled by a car started to sway. The car behind the trailer crashed into it, and then another car did the same.
It is not yet known what caused the crash. Traffic on the E22 was stopped, and southbound traffic was being diverted via Läckeby. Police said shortly before 12 pm that northbound traffic would soon be moving again.