A woman pensioner was killed after running from a car parked next to the A34 into the path of an oncoming vehicle.

Police accident investigators are trying to establish why the 66-year-old from Bicester left the blue Citroen Xsara she was a passenger in and ran out into the northbound carriageway on Tuesday night After leaving the Citroen parked in a lay-by between South Hinksey and North Hinksey, shortly before 7.15pm, the woman ran across the carriageway and was hit by a black Alfa Romeo in the outside lane.

Sgt Mark Ponting, of Abingdon Roads Policing, who is leading the investigation, said: "The woman got out of the car and ran across the northbound carriageway and then she was struck by a vehicle in lane two.

"We have no idea why the woman started to cross the carriageway and that is a central part of our investigation.

"The driver of the Citroen Xsara and the driver of the vehicle which struck the woman are helping us with our inquiries.

"We want to hear from drivers travelling along the northbound carriageway at the time, who may have seen the woman run across the carriageway, or saw her lying in the road."

No-one has been arrested or charged in connection with the pensioner's death.

A spokesman for South Central Ambulance confirmed the woman died at the scene and no-one else was injured. Her name will not be released until she is formally identified by the Oxfordshire coroner.

Pc Andy Wickens of Abingdon Roads Policing added: "This collision tragically took the life of a woman and we urgently require anyone who could help our investigation to come forward.

"If you witnessed the collision or saw this vehicle in the area at this time, I would ask you to contact me."

The northbound carriageway was closed while emergency services and police accident investigators worked at the scene and it was re-opened at 5am today.

Anyone with information should contact Pc Wickens at Abingdon Roads Policing on 08458 505505.