"This a collision where unfortunately recordings, measurements and photographic evidence were inaccurate to determine such factors," accident reconstruction expert Wilma Badenhorst testified.

Moon, 26, is on trial on charges of murder, alternatively attempted murder, drunken driving, and reckless or negligent driving.

He allegedly hit Mavis Ncube while driving down Katherine Street, Sandhurst, in his Mercedes Benz in 2009. She died in hospital.

Badenhorst testified for the defence after prosecutor Roger Mareume told the court earlier that the point of impact was on the side of the road, and not on the road surface.

Badenhorst said the documentation and records she had from police files were not sufficient to determine where Moon actually hit Ncube.

Asked by magistrate Vincent Pienaar what happened when a vehicle exceeded 100km/h when approaching a bend, she said the driver would lose control and the vehicle would spin and go sideways.

She said she could not dispute Moon's version that he travelled at 70km/h and that the point of impact was within the bend when Ncube and her cousin Thandi Sibanda ran into his path.

"No physical evidence was recorded to enable me to calculate the speed of the Mercedes Benz," Badenhorst said.