A pensioner was rushed to hospital after being hit by a car in Bicester Road, Aylesbury.
The accident happened at around 12.20pm on Saturday outside the BP petrol station where a blue Rover MGZS collided with a 94-year-old pedestrian.
He suffered a broken arm and knee and head injuries and was taken to Stoke Mandeville Hospital.
The driver of the car, a 37-year-old man, was not injured in the collision.
Sgt Daniel Collett from the roads policing department said: “An investigation into how the collision occurred has commenced.
“Bicester Road is a busy thoroughfare; there were other pedestrians and users of the local garage and shop nearby.”
Anyone who witnessed the collision or who may have seen either the pedestrian or the vehicle prior to the collision should contact Thames Valley Police on the non-emergency number 101 quoting URN 614 1/8/15.
If you do not want to speak directly to the police you can contact the independent charity Crimestoppers anonymously on 0800 555 111. No personal details are taken, information is not traced or recorded and you will not go to court.