Police are appealing for witnesses following a collision on the A11 in Thetford on Tuesday.
The incident happened at about 8.10pm in the Norwich-bound carriageway near the BP petrol station.
Motorists were forced to take evasive action after an Audi A4 was seen to stop on the side of the road for reasons unknown.
This led to a collision involving five cars, including the Audi which failed to stop and left the scene shortly afterwards. No one was seriously injured.
Officers are keen to trace the driver of the Audi A4, or speak to anyone who may have witnessed the collision or has information concerning the driving manner of the vehicle prior to the incident.
Anyone with information should contact Pc Dave Carter at Acle Police Station on 101.