Seventeen people were taken to hospital in Oxford after a coach overturned as it left the M40 in Oxfordshire.
Five of those admitted to the John Radcliffe Hospital needed surgery, mainly for broken bones. The remaining patients have now been discharged.
The Oxford Tube coach, travelling from London, crashed just before 2300 GMT on Saturday at the northbound exit of junction seven, near Thame.
A man has died in a separate crash which closed the M5 on Sunday.
A coach, a lorry and three cars were involved in the crash in Gloucestershire.
No other vehicles were involved in the M40 incident, Thames Valley Police said.
A spokesman said it was investigating whether the coach took a different exit off the motorway. The Oxford Tube normally leaves at junction eight.
The Stagecoach-owned vehicle is believed to have been carrying 33 passengers.
One person was thrown clear. Another had to be freed from the wreckage.
Some people with minor injuries were treated at the scene.
John Nixon, of Oxfordshire Fire and Rescue Service, said when he arrived he saw the coach on its side on an embankment.
"There were people laid on the side of the embankment, on the road, covered in space-type blankets to keep them warm," he said.
Mr Nixon said his crew's first job was to stabilise the coach, which still had injured passengers on board, to stop it sliding further down the slope.
Six ambulances from South Central Ambulance Service attended the crash scene. Officers closed the slip road, although the motorway remained open in both directions.
A spokesman for Oxford Tube said the coach was understood to have gone through a barrier and ended up on its side.
The driver is not believed to have been seriously hurt but was among those taken to hospital, the company said.
The spokesman added: "Safety is our absolute priority and our immediate thoughts are with those who have been injured in the accident.
"Oxford Tube representatives have attended the scene and arrangements have been made to take passengers who were not injured to their final destination.
"We will be carrying out our own internal investigation and assisting the police in any way that we can with their inquiries into the accident."
Sergeant Steve Blackburn of Thames Valley Police said: "The vast majority [of the passengers] were walking wounded or not injured at all and were released either at the scene or shortly after receiving some treatment."
An investigation into the cause is under way.