A dangerous overtake manoeuvre is believed to have caused an accident which saw three people hospitalised on Thursday evening, police say.
The two car collision, four miles south of Quarff, resulted in firefighters having to use cutting equipment to free people from the wreckage.
Police are now appealing for witnesses to the incident, saying that they believe a vehicle performing a dangerous overtake while travelling southbound on the A970 was behind the smash.
In a statement police officer John Williamson said: “The dangerous overtake forced an oncoming vehicle to take evasive action in icy conditions resulting in a loss of control and a collision with another vehicle.”
Police, two fire engines and ambulance crews were called to the scene at Fladdibister just after 5pm on Thursday night. One lane of the road was blocked until around 6pm.
Witnesses can contact Police by calling 101 or alternatively attend the Lerwick Police Station in person.