Drivers have been facing delays on the M40 north of Bicester and a single-vehicle accident has been reported involving a Mercedes being driven erratically.
Vehicles have been queuing on the southbound carriageway around junction 10 at Brackley for Cherwell Valley Services.
An accident has also been reported between junction nine and junction 10, which temporarily blocked the carriageway at about 5pm.
South Central Ambulance Service spokesman David Gallagher said: "We did get a call about a single-car accident between junction nine and junction 10 northbound on the M40 but the crew sent to the scene was not able to locate it.
"It was reported by the caller that a Mercedes had been driving erratically cutting up other cars and then went off the road having hit a barrier on the hard shoulder."
Two separate accidents on both carriageways between junctions 9 and 10 have been reported.
There has also been an the A34 northbound near Harwell, between the Chilton and Milton interchanges.
For further updates visit the Oxford Mail's live travel updates.
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