Drivers should expect delays on the A11 southbound after a collision closed it near Fiveways Roundabout at Barton Mills this afternoon.
Suffolk Police, who were called just after 3.15pm said the accident happened at low speed between a car, van and articulated lorry. It was about 200 yards on the Elveden side of the roundabout and they put a rolling roadblock in place.
By 4.15pm lane two had reopened and the police were expecting the other lane to open shortly, but warned it would take time for tailbacks to clear.
East of England Ambulance Trust said it has a rapid response vehicle and ambulance crew on the scene but it is not yet known how many people have been injured or how seriously they are hurt.
Fire crews from Mildenhall and Newmarket made the scene safe and assisted ambulance crews.
Drivers are advised to avoid the area.