Buckingham Palace said Philip was examined by a doctor, but confirmed he wasn't hurt.
The BBC reported that Prince Philip's vehicle turned on its side after pulling out of a Sandringham driveway onto a main road and colliding with the Kia.
Roy helped Philip out of his overturned Land Rover.
Norfolk Police said they were following standard procedure where a road traffic collision resulted in injuries.
Speaking about Philip's Freelander, he added: "I didn't see it come from the side road, I saw it careering and tumbling across the road and ending up on the other side".
Kathy Burke has branded Prince Philip a "selfish c**t" on Twitter following his recent auto crash.
Other witnesses said there was a "blinding" sun in the sky at the time of the crash.
"We are aware of the public interest in this case, however, as with any other investigation it would be inappropriate to speculate on the causes of the collision until an investigation is carried out", Norfolk Constabulary said in a statement.
A 45-year-old woman in the other vehicle broke her wrist, but the other passengers - a woman and nine-month-old baby- were uninjured.
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The Queen was spotted driving her Range Rover without a seatbelt a day after Prince Philip's crash.
Philip showed former USA president Barack Obama and his wife Michelle the personal touch when he drove them and the Queen to Windsor Castle after the Marine One presidential helicopter landed close to the monarch's Berkshire home during their visit to the United Kingdom in April 2016.
The women in the auto reportedly received minor injuries as a result of the crash, but the nine-month-old baby boy escaped without injury.
During a recent appearance at Lancashire, a reporter asked the 68-year-old how the Duke of Edinburgh was faring.
"I rushed to the other auto - there was smoke coming out as if it may explode".
The Palace confirmed that Philip wasn't injured in the collision.
Mr Warne, who was one of the first motorists on the scene, told The Sun newspaper he overheard Philip telling police he had been "dazzled by the sun".
Philip retired from public life in 2017, although he still occasionally appears alongside his 92-year-old wife at official engagements.
The driver of the Kia and her passenger were taken to hospital where they were treated for minor injuries and later discharged.
The Queen has never had to do a driving test and is the only person in Britain allowed to sit behind the wheel without a licence.
Drivers in the United Kingdom aged 70 and above need to reapply for their license every three years, for which there is a mandatory eyesight test.
Driving himself by auto has been his most enduring pleasure.