Motorists faced standstill traffic on the A14.
Queues built up on the major road between Sproughton and Copdock at around 6pm on Wednesday.
Witnesses reported the congestion was due to a car fire.
A spokesman for Suffolk Fire and Rescue Service said crews were called to an incident at junction 55 on the westbound carriageway at 6pm, but it turned out to be a false alarm.
Suffolk police and the East of England Ambulance Service have also been contacted for comment.
