Drivers are facing long tailbacks in Kidlington after a lorry carrying a 10-ton load tipped on its side this morning.
The accident at the Sainsbury's roundabout, on the A4260, has left Five Mile Drive, Water Eaton Park and Ride and the roundabout closed since about 11am.
Some bus passengers trying to get back to Kidlington have been left stranded in Oxford due to the park and ride closure and delays are also reported on the A44 Woodstock Road.
A recovery team is at the scene but police are unable to say when the lorry will be moved.
Thames Valley Police spokesman Andrea Bennett said: "The driver was stuck in his lorry but managed to climb out.
"Traffic has been very heavy all day because of the closures. It is a difficult vehicle to move and at the moment we don't know when the roundabout and roads will be re-opened."
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