Five people have been taken to hospital and four horses have died after a four-wheel drive towing a horse float crashed into a tree stump in Tasmania's north.
The white Ford Ranger crashed at 1:45am on Monday after leaving the Batman Highway at Rowella, north of Launceston.
Police were automatically notified via a crash detection feature on one of the passengers' iPhones and reached the scene in eight minutes.
The occupants, ranging from 14 to 20 years of age, were all taken to the Launceston General Hospital.
Police initially said one was taken to Melbourne and another to Hobart for treatment but later said this was incorrect.
One person has since been released.
The driver was a 20-year-old woman, police said.
Tasmania Police said two of the four horses being transported died immediately after the crash when the horse float rolled, while the other two had to be euthanised at the scene.
Police officers from the Exeter, George Town and Launceston stations attended the crash.
Crash investigators and forensic officers remain at the scene, with investigations into the cause of the crash ongoing.
Tasmania Police Inspector Ruth Orr said initial investigations suggested driver fatigue "probably would've been involved".
"They had been in Hobart with the horses attending a race meeting, and at the conclusion of the race meeting last evening (Sunday) they were travelling back to Rowella," she said.
"I'm advised that the owner of the horses attended prior to the vet arriving, and euthanised the other injured animals."
Of the automatic crash alert sent by one of the occupant's mobile phones, Inspector Orr said the quick response time was helped by police being "in the area on an unrelated matter".
"But in a case where people had lost consciousness in a crash like this, it is certainly something that alerts police quickly."
Inspector Orr urged people to take care on Tasmanian roads.
"Injuries and crashes on our roads this year so far are already significantly higher than last year," she said.
People who saw the Ford Ranger prior to the crash are asked to contact police or Crimestoppers.
In a Facebook post, Yoles Harness Racing Stables confirmed members of their team were involved in the crash, thanking the public for "reaching out offering support".
