A two-year-old girl has been engulfed in flames after her 19-year-old father allegedly tried to avoid a random breath test and wound up hitting a pole, killing them both.

Alex Peart, 19, was stopped in a line of traffic at an RBT on the Tasman Highway in Sorell in Hobart on Thursday at 9.10pm, when he made a U-turn and lost control of his Holden Vectra.

Police said in a statement that the 19-year-old man from Midway Point and his toddler daughter Ruby were killed in the single vehicle crash on the Tasman Highway, in Sorell, about 9:10pm on Thursday.

View photos Mr Peart's daughter Ruby was just two years old. Source: Facebook More

Female passenger Xanna Rose Weavell, believed to be the girlfriend of Mr Peart, survived the crash with minor injuries.

She was later taken to the Royal Hobart Hospital for observation.

"Police were conducting a static random breath testing (RBT) site on the Tasman Highway Midway Point at the roundabout with Penna Road," police said in a statement.

According to the ABC, police said the man's car stopped in the line of traffic before it made a U-turn and travelled back towards Sorell, overtaking other vehicles.

View photos Xanna Weavell, the late Alex Peart, and Mr Peart's late daughter Ruby. Source: Facebook More

The driver lost control soon after, hitting a pole, with the impact causing the vehicle to break into two.

"The rear of the vehicle remained in contact with the pole and the front came to rest in the westbound lane," police said.

The car burst into flames and both Ruby and her father were unable to be saved.

View photos Ruby has been described by a family friend as the 'sweetest' little girl. Source: Facebook More

A friend of the family told the Daily Mail that Mr Peat's daughter was the "sweetest and the brightest little girl."

"They are [both] so very loved and will be missed by so many," the friend said.

Anyone with information is asked to call Tasmania Police on 131 444 or Crime Stoppers on 1800 333 000.

News break – September 16