Thames Valley Police is appealing for witnesses to a serious road traffic collision in Weston Turville.
It happened at around 4.40pm on Friday 17 January between an unknown vehicle and a cyclist on the Halton Airfield Road, between Western Turville and RAF Halton.
The cyclist, a woman in her sixties, was taken to Stoke Mandeville Hospital with serious head injuries. She is now in a serious but stable condition.
The driver of the vehicle did not stop following the collision but the passenger side wing mirror was damaged.
Investigating officer PC Tom Smith of the Roads Policing Unit in Buckinghamshire, said:
“I am appealing for any witnesses of this collision to come forward.
“This happened on an unnamed road but other motorists in the area at the time may have seen this incident happen.
“Anyone with dash-cam is also asked to check the footage for anything of note that could help with this investigation.
“If you think you could be the driver, please contact Thames Valley Police.
“The non-emergency number is 101 or if you have details you think could help, please use the online form, quoting the reference number 43200019294.
“You can also make a report, 100% anonymously, by contacting the independent charity Crimestoppers on 0800 555 111.”