Six people have been taken to hospital after five vehicles were involved in a crash.
The accident happened on the eastbound carriageway of the A14 near Stowupland in Suffolk, at about 12:40 GMT.
The East of England Ambulance Service said three people were taken to West Suffolk Hospital, two to Addenbrooke's Hospital in Cambridge and one was transported to Ipswich Hospital.
The road has since reopened, Suffolk Police said.
The fire service and ambulance, including air ambulance, also attended. The road was closed on the A14 eastbound at the A1120 junction but later reopened.
Officers would like to hear from any witnesses and have asked for any motorists with dashcam footage to contact them.