The driver accused of killing a Black Hill pedestrian was travelling at 96km/h before losing control of his car, a jury has been told.

The Ballarat jury was told on Thursday the car was travelling about 71km/h when it hit Patrick Bell, throwing him 22.9 metres in Chisholm Street shortly after midnight on June 30, 2015. The 17-year-old died in hospital from multiple injuries.

Nathan White, 36, has pleaded not guilty to culpable driving causing death and dangerous driving causing death.

Collision reconstruction unit Detective Sargeant Janelle Megan, who is a doctor of philosophy, told the jury the accused's car was travelling about 96km/h at the first of four tyre marks on the road.

"We call it a point of loss of control. The vehicle was already out of control but we can only work with the physical evidence that was there," Dr Megan said.

She said when the car hit Patrick, it was travelling about 71km/h. Dr Megan said the car hit a pole less than a second before hitting Patrick with its rear right corner.

The car's path then changed, rotated anti-clockwise and hit a tree, she said. Patrick was thrown 22.9 metres, coming to rest in a driveway.

The Crown prosecutor and defence barrister asked Dr Megan a number of times to explain to the jury the measurements and calculations used to determine the car's speed.

During cross examination, defence barrister Anthony Lavery criticised Dr Megan for using a mechanically sound car for the skid test, rather than using White’s Holden Commodore.

“After the accident it had one fully deflated tyre. One of the other tyres was inflated but it was well below the recommended level,” Mr Lavery said.

But Dr Megan said this would not change the value of the skid test, saying the test had nothing to do with break performance but the sliding resistance between the tyres and road surface. 

White was driving to his Brown Hill home after playing pool at Nicholson Street house when he allegedly hit the pedestrian. The trial continues in the County Court on Friday.