The court heard that the driver of the vehicle behind Miss O'Brien first noticed Miss O'Brien's vehicle when it started to make sudden movements and smoke came off the left rear tyre.
The driver then saw the car do a small zig zag, like an over-correcting move.
The driver dropped back her own speed, then saw Miss O'Brien in front reach her left hand backwards into the rear seat. She then saw the vehicle do another zig zag and then Miss O'Brien put her hand back on the wheel and immediately the car crossed to the other side of the road and crashed into the vehicle coming in the opposite direction.
Dr Bain said the court could conclude that the evidence showed that Miss O'Brien reached into the back seat and thereafter lost control, there was a zig zag movement and the lack of proper tyres may have contributed to the car losing grip on the road.
The rear right tyre was a space saver, the court heard.
Miss O'Brien was using a vehicle borrowed from an associate for about four weeks.
Police presented evidence that Miss O'Brien was checked at the scene for seatbelt marks but nothing could be seen on her stomach or shoulder. This suggested Miss O'Brien was not wearing a seatbelt.
Miss O'Brien's parents were at the inquest, held this morning, and were relieved at the evidence which cleared their daughter.
