Traffic was brought to a standstill on the A34 throughout Oxfordshire today after a crash between a tanker and a lorry carrying flour.
One driver needed hospital treatment after the two lorries collided near Bicester.
The accident happened at 11.30am on the northbound carriageway, between the Weston-on-the-Green turn and junction nine of the M40.
The air ambulance was called to the scene, but a land ambulance was used to take the driver to Oxford's John Radcliffe Hospital.
His injuries were not thought to be life-threatening.
The accident caused lengthy tailbacks with traffic stretching back to the Botley interchange and beyond.
Martin Dellar, a spokesman for the Highways Agency which manages the road, said traffic was reduced to one lane following the crash.
The southbound carriageway was also closed for a short time to allow the air ambulance to land.
He added: "Traffic was diverted at the Pear Tree interchange and the effect on traffic has been moderate.
"Inevitably some disruption was caused but traffic is not as heavy in the middle of the day, and it would have been worse if the accident had taken place during rush-hour."
The northbound carriageway was reopened at 2.30pm after police accident investigators finished working at the scene and Highways Agency officers removed debris from the road.
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